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Growth & Development
Trees, turfgrasses, shrubs, flowers and vines make up the majority of plant types on your grounds. Common aspects of these plants are that they are all highly evolved and that they have similar characteristics of growth and development. Most notably, they are all vascular seed plants, they all conduct photosynthesis, and they all derive nutrients and water from their surroundings.
All seed plants have flowers that are made up of reproductive structures (stamens and pistils) and non-reproductive structures (petals and sepals). Flowers bear the seed that contains the embryo that can develop into a new plant.Three vegetative organs—the root, stem and leaf—are easily recognized. These organs are responsible for extracting
water and nutrients from the soil and transporting them through a plant, providing plant structure and anchorage, and conducting photosynthesis. Fundamental to an understanding of plant anatomy and function is an understanding of the interrelationship and interdependence of plant parts. Seed plants start as rudimentary embryos and develop roots, leaves and flowers initially in that order. Each plant part develops from undifferentiated cells and becomes a more distinct organ. Consequently, the separation of the plant into discrete,
defined organs is only approximate. You won’t find a line dividing leaves from stems or roots from stems, but you will find a gradual change in cell structure and organization where two organs join.
Plants are made up of many individual basic units called cells. Cells are the smallest biological unit having characteristics of life. They have the ability to extract substances from their environment and continually adapt to their environment; and they have a unique chemical composition, structure, metabolism, growth, reproduction
and organization. Although plant cells differ depending on their function, you can visualize a generalized, undifferentiated, unspecialized plant cell. On the outside of the cell is the primary cell wall, which encloses the cytoplasm in which you find deposits called inclusions (oil and fat droplets, spherosomes, protein bodies, starch grains and crystals) and metabolic bodies called organelles (nucleus, plastids, mitochondria, Golgi bodies and ribosomes). The cytoplasm is a semifluid substance that is pressed against the cell wall by a central vacuole. The vacuole is filled with a watery solution of dissolved inorganic and organic molecules, as well as some insoluble material.
The plasma membrane separates the cytoplasm from the primary cell wall. Another cell membrane, the tonoplast, envelopes the vacuole and separates it from the cytoplasm.
The last generalized plant-cell feature is the plasmodesmata, which are strands that extend through cell walls and connect the cytoplasm of adjoining cells.The organelles in the cytoplasm have distinct functions. Chloroplasts are the bodies in which photosynthesis takes place. The nucleus contains all the genetic material needed for cell reproduction. Respiration takes place in the mitochondria.
A seed plant is made up of many individual cells, which are cemented together. You will find several different types of cells in plants, and when you group them together as a distinct functional and structural unit, you call them tissue. The major tissues of vascular plants are the dermal, vascular and fundamental (ground) tissues. The dermal tissues (epidermis and periderm) make up the protective structures of a plant. Vascular tissues are a plant’s conducting tissues. Generalized plant cell showing the complexity of many subcellular bodies surrounded by membranes. Membranes divide the cell into compartments and subcellular bodies. A cell must maintain the integrity of these membranes if it is to survive and function.Peroxisomes Chloroplasts Nucleus Plasma membrane Cell wall MitochondriaVacuoleTonoplast Parenchyma cell. Cell types.Collenchyma cellsSclerenchyma cell Vascular tissues include the xylem (water conducting) and phloem (food conducting) tissues. Fundamental or ground tissues make up the basic substance of plants and include three distinct types: parenchyma, col-lenchyma and sclerenchyma . Parenchyma cells are living and capable of growth and division. They are responsible for photosynthesis, wound healing, storage and new growth. Collenchyma cells also are living and capable of producing new growth but consist of thick-walled cells and mainly serve as supporting tissue in leaf veins and stems. Sclerenchyma are thick-walled cells that may or may not be living at maturity. Sclerenchyma function
in a structural role and are made up of fibers (slender elongated cells) and sclereids (cells that vary in form from branched to elongated to relatively concentric).
GROWTH AND GROWING POINTS
Growth is defined as the increase in size by cell division or cell enlargement. This increase in size results from the plant taking up air, water and nutrients and incorporating
them into its structure. Light energy is the driving force behind growth. As mentioned above, parenchyma and collenchyma cells are living and capable of dividing to produce new tissue. Tissue that is actively dividing to produce new tissue is called a meristem. Meristems are actually the growing points on a plant Buds on branches of trees or the apical meristem on the top of turfgrass crowns are examples of growing points. Growing points give rise to new leaves, flowers, branches and roots. Keeping these growing points alive and active is the key to growing plants.
Roots are responsible for extracting moisture and nutrients from the soil and anchoring the plant in the soil . Roots originate from the growing embryo and are the first structure to emerge from the seed during germination.
This first root developing from the embryo is called the primary root, or taproot, and all other roots are called adventitious roots—roots arising from any organ other than the embryo. Roots consist of a growing point at the tip, which is protected by a root cap; the epidermis on the outside of the root; the cortex, which makes up the flesh of the root; root hairs, which absorb moisture and minerals; and the vascular cylinder, which includes the xylem, phloem, cambium and pericycle. Roots add new growth via the growing points at their tips. Roots of most woody species primarily are concentrated in the top 3 feet of soil and can spread two or three times the diameter of the spread of branches, also referred to as the drip line of a tree. But surprisingly, the most active portion of a woody-plant root system is about 6 inches deep and only reaches out to the drip line of the tree. By contrast, the most active zone of grass-root water absorption is only about 1 inch deep.Root systems are broadly divided into either fibrous-root or tap-root systems. Fibrous roots are multibranched and brushlike and are typical of mature grasses and certain trees and shrubs. Taproot systems consist of one main root that grows deep in the soil. Under dry conditions, plants with tap roots are able to extract water from deep in the soil. However, tap-rooted plants are more difficult to transplant because they lack the extensive branching close to the soil surface that fibrous-root systems have. This branching tends to hold the root ball together and produce more small roots for extracting moisture from the soil.
Stems are the connecting structures between the leaves and roots. It is through the stem that water and nutrients are transported to the leaves from the roots, and carbohydrates are conducted from the leaves throughout the plant. Stems consist of nodes separated by internodes with buds developing at the nodes. Buds can give rise to leaves, flowers and lateral stems. A shoot is a general term Axillary budDormant budPeridermRoot hairsApical meristem of main shootApical meristemof axillary shootStem withyoung peridermStem withscaly barkTaproot withperidermLateralroot Root capenclosing root apical meristemFigure 3. This illustration shows growing points of a young perennial dicot.Root hairs1 mmCasparian stripCell elongationzoneApical meristemRoot capRegion of cell differentiation1 mmEndodermisCortexEpidermisVascular tissuePericyclePhloemCambiumXylemCortexEpidermisEndodermisRoot hairsCasparian stripFigure 4. Illustration of a root longitudinal section and cross section.
The crown consists of a series of nodes with unelon-gated internodes. The crown is the key to survival of turfgrasses.
Leaves grow from the crown and envelope the growing point. You can cut the leaves off turfgrass plants or injure them, but the plants will live as long as the crowns stay alive.At certain times of the year, turfgrasses produce a flowering culm. A culm originates from the top of the crown, consists of nodes and internodes, and terminates with a flower or florets. Alternately appearing on either side of the crown is a series of axillary buds that give rise to lateral stems, such as tillers, rhizomes and stolons. Lateral stems are elongated stems with nodes and elongated internodes. When the lateral stem grows up within the leaf that lies under the node, it is called a tiller. All grasses produce tillers that generally do not spread far from the mother plant. Some grasses vegetatively spread by tillering alone, and these are called bunch grasses. Perennial ryegrass is an example of a bunch grass. When a lateral stem grows horizontally through the leaf that lies below on the crown, it is called a rhizome or stolon. Rhizomes (see Figure 7, below left) grow horizontally under the ground, may branch or root at nodes and produce a new plant at their tip(s). Stolons are similar to rhizomes but grow on top of the soil. Examples of rhizomatous grasses are Kentucky bluegrass and creeping red fescue. Rough bluegrass and bentgrass are stoloniferous grasses. Some grasses, such as zoysiagrass and bermudagrass, spread by rhizomes, stolons and tillers. It’s important to reinforce the fact that both rhizomatous and stoloniferous grasses also produce tillers, but bunch grasses vegetatively spread only by tillering.
Because the leaf is the chief site of photosynthesis, it is critical that you understand its structure before going on to learn about photosynthesis. The major tissues of a leaf are epidermis, mesophyll and vascular bundles (see The epidermis is like the skin on a leaf. It is a single layer of cells and is covered with a cuticle—a wax-like layer that seals the leaf from movement of gases and water into and out of the leaf. One peculiar structure of the epidermis is the stomate—the pore through which water and gases, such as carbon dioxide and oxygen, flow into and out of the leaf. The unique geometry of guard cells on either side of the stomate allows them to open and close the stomate in response to fluctuations in their turgor pressure. Stomates generally are open during the day and close at night or when moisture stress occurs. When stomates are open, water can leave the plant in the form of vapor, thus cooling the plant. This water vapor loss is called transpiration. In grasses, leaves are composed of two parts—the blade BladeSheathGrowing pointPrimordial leavesAxillary budAdventitious root#RootsCrownYoung leafThird young leafNext youngest leafPrimary rootYoungest leafInflorescenceCollarFlowering culmFigure 5. This generalized grass exhibits both stoloniferous and rhizomatous growth. Note that it also produces tillers like all grasses. A flowering culm extends from its crown.AuricleLiguleLeaf bladeTillerLeaf sheathStolonRootsRhizomedaughterplantRhizomeStolondaughterplantSenescingleafFigure 6. Generalized turfgrass crown.Mature cataphyllElongating cataphyllElongating internodeGrowing pointOld cataphyllAxillary budNodethat refers to the stem and its associated leaves. In the case of grasses, three types of stems exist: the crown, flowering culm and lateral stems (see Figure 5, above right). The crown is the primary stem of grasses; it is from the crown that leaves, flowering culms and other stems originate (see Figure 6, below). Figure 7. Detail of the tip of a Kentucky-bluegrass rhizome.
and the sheath—that are connected by the collar region (see Figure 9, above). The collar region is especially important in identifying turfgrasses. Structures, such as ligules (a membranous or hairy tissue at the base of the blade), auricles (appendages at the margins of the leaf in the collar region) and collars (the back sides of the leaves in the collar region) may vary among the turfgrasses. FLOWERS Flowers are the reproductive organs of plants. They consist of male and/or female parts (see Figure 10, below). Some plants produce separate male and female flowers, and other plants produce flowers with both male and female parts. Some entire plants are either male or female. This can be important for ornamental species. For example, many fruitless trees are merely male plants. The male flower parts consist of the stamen composed of an anther and a filament. The anther holds the pollen grains, which give rise to sperm. The female portion of the flower is the pistil. It is commonly flask shaped, with a swollen basal portion called the ovary connected to a stalk-like style topped off with a swollen portion at the tip called the stigma. In most cases, pollen must be transferred from the anther to the stigma for the pollen tube to germinate and transfer the sperm to the ovary for fertilization to occur and embryo and seed to develop. One exception occurs in Kentucky bluegrass, where an embryo is developed
in the flower from cell division of the vegetative tissue in the ovule. This process is called apomixis and is the reason why most seeds of Kentucky bluegrasses are genetically identical, like a clone. PLANT PHYSIOLOGYWe mention that light energy is the driving force behind growth, and plants accomplish this through the process of photosynthesis. Photosynthesis involves activation of chlorophyll (the green pigment in leaves) molecules by light combined with the assimilation of carbon from the air as carbon dioxide to form glucose sugar (a carbohydrate). Carbohydrates are the actual food plants rely on for growth. Photosynthesis is actually a combination of two separate
but related processes—a light reaction and a dark reaction In the light reaction, the chlorophyll molecule changes to an excited state when exposed to blue or red light. During this light phase of the reaction, water is split into oxygen (which the plant expels), electrons (which are transferred to produce photochemical energy in the bonds of adenosine triphosphate
[ATP]) and hydrogen ions (which are used to create another high-energy molecule called the reduced form or nicotinomide adensine diphosphate [NADPH]). The high-energy bonds in ATP and NADPH are then used to drive the second reaction called the dark reaction. In the dark reaction, carbon dioxide from the atmosphere
enters the plant through openings— stomates—in the leaves. In most plants, carbon dioxide immediately reacts
with a five-carbon molecule called ribulose-bisphosphate
(RuBP) to form a three-carbon compound called 3-phosphoglycerate (3-PGA) in a reaction catalyzed by the enzyme RuBP carboxylase. Because the first molecule formed after carbon dioxide is fixed is a three-carbon molecule, we call plants with this carbon-fixation system C3 plants. One problem encountered by C3 plants is that the same enzyme that catalyzes the fixation of carbon dioxide from the air also can fix oxygen from the air and lead to photorespiration
and a net loss of carbon dioxide. Some plants (primarily monocots) have a different way of fixing carbon dioxide from the air. They get around the problems of photorespiration through their unique plant anatomy and additional enzyme systems for fixing carbon dioxide (see Figure 13, at right). In these species, a three-carbon molecule called phosphoenol pyruvate Figure 8. Cross section of a leaf showing the major tissue types: dermal, vascular and fundamental (ground) tissues.Phloem (vascular)Upper epidermis (dermal)Palisadeparenchyma (ground)SclerenchymafibersXylem (vascular)ChloroplastsCuticleIntercellular air spaceStomateVascular bundleSpongyparenchyma (ground)Lower epidermis(dermal)Bundle sheathImage not found on CD for Figure 9.PetalSepalOvaryReceptacleStamenFilamentAntherStamen detailPistil detailStigmaStyleOvaryOvulePistilFigure 10. Flower parts.
(PEP) reacts with carbon dioxide from the air to form a four-carbon molecule called oxaloacetic acid (OAA)—thus the name C4 plants. The enzyme that catalyzes the carbon-dioxide fixation is called PEP carboxylase, and it only fixes carbon dioxide and not oxygen. Eventually OAA is converted to malic acid, which moves out of the cytoplasm—or mesophyll cells—and into the chloroplasts of tightly packed bundle-sheath cells. There the malate splits off a carbon-dioxide molecule, which is picked up by RuBP carboxylase, the same enzyme that fixes carbon
dioxide from the air in C3 plants. Because the RuBP carboxylase is compartmentalized in bundle-sheath cells and not exposed to oxygen in the air, no photorespiration takes place in C4 plants. ATP and NADPH from the light reaction are then used in the next two reactions. Eventually these phosphorylated
sugars transform into glucose, fructose and other simple sugars.Because photorespiration is more of a problem in warmer temperatures, C4 plants tend to be better adapted to warmer climates, where they evolved the C4 process to avoid photorespiration. Further, species that possess the C4 mechanism and anatomy mostly (though not entirely) are monocots, especially grasses and sedges. Therefore, turfgrass scientists have found it useful to distinguish C4 turfgrasses from C3 turfgrasses with the terms warm-season species (C4 plants) and cool-season species (C3 plants). Virtually all trees and shrubs grown in North American landscapes are C3 plants, so the distinction is not as useful in the ornamental industry, where these terms are not used in this regard. Once simple sugars are produced through photosynthesis,
they can be converted to more complex sugars, such as sucrose, starch, fructosans or structural carbohydrates such as cellulose. In the case of cool-season grasses, the primary storage carbohydrate is fructosan—a long chain (2)NADPH(2) ATPATPCO2H2OStarch(2) Triose phosphate(3C)3(3C)(2) 3-phosphoglycerate RuBP carboxylase enzyme(1) Ribulose-1,5-bis-phosphate (5C)Sugar phosphates(2C, 3C, 4C, 5C, 6C, 7C)(1)Hexose phosphate(6C)Ribulose-5-phosphate12Figure 11. The C3 cycle involves three steps: 1) Formation of a CO2 receptor and its incorporation of carbon from CO2 to form two molecules of a three-carbon molecule (thus C3 cycle), 2) production of triose phosphate using the energy from ATP amd NADPH from the light reaction, 3) production of phosphorylated sugars and regeneration of the five-carbon phosphorylated sugar that started the cycle off.WARM-SEASON VS. COOL-SEASON GRASSES WARM-SEASON SPECIES# Optimum temperature: 85° to 105°F# Slow to green in spring# Quick to go dormant in fall because of photodestruction of chlorophyll at temperatures less than 60°F and cold-sensitive enzymes, which fix carbon dioxide from the air# Best growth in summer# Not very cold hardy# No photorespiration and better photo-synthetic efficiency. COOL-SEASON SPECIES# Optimum temperature: 50° to 77°F# Best growth in spring and fall due to cooler temperature and lower photorespiration# Cold hardy# Photorespiration occurs.Air3 phosphoglyerate(3C)Phosphoglycolate(2C)RuBPcarboxylaseenzymeRuBP(5C)O2PhotorespirationFigure 12. Photorespiration. The same enzyme catalyzing the initial reation in the C3 cycle where CO2 is picked up from the air can also pick up oxygen instead. This leads to photorespiration.Oxaloacetate (4C)NADPHPEP carboxylase enzymeMalatePyruvateMalateNADP+CO2C3 CycleCO2BundlesheathcellPyruvateMesophyllcellEpidermisSugarPhosphoenol pyruvateATPFigure 13. Warm-season plants initially pick up CO2 from the air with a different mechanism than cool-season plants. The first product is a four-carbon molecule (thus C4 cycle). The CO2 is then shuttled to another part of the leaf that is protected from the surrounding air. It is here that the CO2 goes through the C3 cycle.Airof fructose with a terminal glucose. Warm-season grasses store sugars as starch. The sugars that the plant stores then are broken down by the plant and used for growth. This process is called respiration. Both plants and animals carry on respiration
and use the same biochemical pathways. Oxygen is required for respiration, and carbon dioxide is expelled (the opposite).
Soil scientists define soil in various ways, but all definitions illustrate the fact that soil is not as simple as many assume. Soil is the uppermost layer of material covering most of the earth’s land surface
and consists of mineral particles, organic matter, microorganisms, water and air. The possible types and proportions of these components are innumerable, which is why so many different types of soil exist.Soil scientists divide soil into layers they call horizons. The A horizon is the uppermost several inches and consists
mostly of what we know as topsoil. It is often dark in color and rich in organic matter, and it usually provides a favorable environment for plant growth. The next two layers, the B and C horizons, are lighter in color, lower in organic matter and relatively infertile. We call the B and C horizons subsoil. Plant roots generally extend through the A horizon and well into the B horizon. However, the C horizon, which may be well below the surface, is comparatively inhospitable for root growth. In landscape situations, this natural layering often is absent due to soil movement during construction. All too often, this means that no topsoil layer is present, forcing the landscape installer to modify the existing subsoil to make it more favorable to plant growth.Aside from horizons, which describe the position of the soil layer, soil scientists also refer to soil fractions. Fractions
refer to organic or inorganic (mineral) substances. Thus, most soils are composed partly of a mineral fraction and partly of an organic fraction. A few soils are almost completely organic, and others are mostly mineral.• The mineral fraction of soil, consisting of particles that ultimately originated from rock, comprises the largest percentage of most soils. The type of rock from which the mineral particles originated has some bearing on the chemistry of a soil. However, the mix of particle sizes has a greater impact on soil quality and how you must manage it. The age of the soil and how much weathering it has undergone determine particle size: Older, more weathered soils consist of smaller particles. The smallest particles are clay. Larger (but still quite small) particles are silt, and the largest particles (that still qualify as soil) are sand (see table, “Sizes of soil particles,” above right). Soils rarely, if ever, consist of solely one size of particle. Thus, soils are classified according to the proportion of each particle size they contain—we commonly refer to this as soil texture (see Figure 1, at right).Texture, in the broadest sense, is stated as coarse (sandy soils), medium (silts or loamy soils) or fine (clayey soils). Loamy soils are intermediate in nature and not totally dominated by the characteristics of any particular particle
size, though they proportionately contain
more silt than sandy or clayey soils. Thus, there is no such thing as a loam particle,
only loam soils. Loamy soils generally have the best overall characteristics for plant growth. To be even more specific, we combine these terms. For example, sandy clay has significant amounts of sand but is dominated by clay particles and clay characteristics. A sandy loam is a mix of particle sizes not totally dominated
by characteristics of any particle size, but—due to a somewhat higher relative sand content—its qualities tend toward those of sand. Other terms you’ll often encounter
to describe texture include light and heavy, referring
to sandy and clayey soils, respectively. As we’ll see, texture, more than any other single aspect, determines the manageability of soils (see sidebar, “Testing for texture,”
page 9).• Organic matter (OM), the other soil fraction, is present
in most soils, but content varies widely. Soils low in organic matter may have less than 1 percent OM content, whereas highly organic soils range far higher. Most soils contain less than 10 percent, and many—especially in arid climates—hold only 1 or 2 percent OM.OM results from decaying plant material. This decay is brought about mainly by bacteria and fungi that consume plant matter as food. The resulting residues are a rich mix of organic materials that usually have a positive effect on 803020100109080307060405050406070201090sandsandsandyloamloamsandyclay loamloamyclay loamsandyclayclay (40%)siltloamsiltsiltyclay loamsiltyclayclaysilt (40%)sand (45%)Clay separate, %Silt separate, %Sand separate, %201030405080901006070100Figure 1. The “soil triangle” shows the 12 textural classes recognized by the U.S. Department of Agriculture. If you know the percentage of each component present in your soil, you can use the triangle to determine the textural class to which the soil belongs. SIZES OF SOIL PARTICLESParticle typesDiameter (millimeters)GravelAbove 2.00Very coarse sand1.00 to 2.00Coarse sand0.50 to 1.00Medium sand0.25 to 0.50Fine sand0.10 to 0.25Very fine sand0.05 to 0.10Silt0.002 to 0.05ClayBelow 0.002
soil quality. As complex organic molecules break down into simpler forms, the organic matter eventually arrives at a semi-stable form we call humus—the dark-colored substance we commonly associate with “rich” soil.Humus contains a variety of carbohydrates, proteins, lignin, cellulose and other materials, but its main benefit does not lie in its nutritional content (most of which is unavailable to plants). Humus improves the physical structure and chemistry of soils so that they have better
water- and nutrient-holding capacities and greater permeability. Notably, humic acid causes clay particles to aggregate into larger particles that act more like sand than clay. This improves drainage and aeration and so is especially valuable in clay soils. Before plant material undergoes extensive decomposition—that is, before it becomes humus—it still is beneficial to soil because it improves physical structure. As stated above, most of the nutrients in humus are unavailable to plants. Eventually, however, even humus can break down into inorganic compounds by the process of mineralization. At this point, nutrients become available to plants again, and the cycle is completed. The reverse of this process is immobilization, wherein microorganisms assimilate inorganic substances into organic compounds. Both of these processes are ongoing in soil, but the overall trend—not counting plant uptake of nutrients—is always toward mineralization.• Water is present in all soils. Texture has the greatest effect on how much water soil can hold: Finely textured soils hold more water than coarse soils. This is because of how soil particles hold onto water molecules. Water molecules “stick” to soil-particle surfaces by a force called adhesion because they possess positive electrical charges that are attracted to negative electrical charges on the soil particles. Thus, a layer of water surrounds soil particles. Even soils that may seem dry have very small layers of water around each particle (though this water may be unavailable to plants). Sandy soils hold the least amount of water due to low soil-particle surface area. A given volume of clay soil, because of the greater number of particles present, contains a far greater surface area onto which water molecules can cling and so has excellent water retention. • Air is present in the pore spaces between soil particles.
Because water is the other substance that can occupy significant amounts of pore space, air content is determined to a large extent by how wet soil is. The presence of air—particularly oxygen—in pore spaces is as important to most plants as water. Thus, good aeration is an important physical property of soil. Soils that hold a great deal of water are low or lacking in oxygen. That is why plants languish in saturated soils—their roots starve for oxygen.• Living organisms are prevalent in nearly all soils. Bacteria,
fungi, protozoans, nematodes and larger creatures such as earthworms inhabit soils, where they live on decaying plant matter and each other. From a soil-management
standpoint, the main benefit of soil organisms is their role in decomposing organic matter, which we discussed above. Warm, moist conditions favor the activity
of these organisms, so these types of climates favor rapid decomposition of organic matter. However, warm moist climates also favor rapid plant growth, which adds more raw material for the decay process. Thus, the cycling occurs more rapidly and on a larger scale. HOW SOIL TYPE AFFECTS MANAGEMENT• Water movement. Because soil particles are solid, water obviously cannot move through them. Instead, it must move around them. Water’s movement in and through soil depends on the arrangement and size of the soil’s pore spaces—the spaces between soil particles. Due to the random way soil particles pack together, pore spaces vary in size. Some are large and some are small. A “typical” soil may be about 50 percent pore space—25 percent small pore space and 25 percent large pore space. The proportion of soil occupied by pore space is its porosity and varies a great deal among soil types. When water drains through a soil, most of its movement
is through large pores. Coarse-textured soils have more large pore spaces than finely textured soils, and air normally fills these large pores. Larger pores are much better at conducting both air and water through the soil, and that’s why sandy soils have excellent drainage and aeration. The rate at which water can flow through a soil is called hydraulic conductivity. Coarser, sandy soils, with their larger pore sizes, have higher hydraulic conductivity than fine, clay soils, which tend to be lower in oxygen and retain more water.Small pores more often contain water, rather than air. Because clay soils have more small pores and greater water YTESTING FOR TEXTURE You can perform a test that gives you a rough idea of soil texture with a Mason jar. Fill a Mason jar about one-third full of soil. Pack it in and then mark the soil level on the side of the jar. Then add water until the jar is about three-fourths full. Cap the jar and shake it vigorously for several minutes. Then set the jar down and allow the soil particles to settle. After a minute or so, the sand particles will move to the bottom. In a few more minutes, silt will start to settle out, and you will see layering in the sediment in the jar. After an hour or so, the silt will have settled completely, but the clay still will be suspended in the water. Measure the depth of the silt and sand layers and compare them to the original
soil level. This gives you an idea of the percentage of these components present in the soil. Subtract these two values from 100, and the remainder is the percentage of clay. For example, if you measured the packed soil in the jar at 4 inches and, after settling, you had 1 inch of sand and 1 inch of silt in the bottom of the jar, the soil would be 25 percent sand, 25 percent silt and the remainder—50 percent—would be clay.
retention, they also are more prone to saturation due to heavy rainfall or poorly drained conditions. When water completely occupies all the pore space in soil, the soil is saturated. Saturated soils, as we mentioned, lack oxygen and therefore make poor environments for root growth.However, clay soils have their benefits as well. For example, they hold more available water and nutrients, so plants can last longer between irrigations and fertilizer
applications. Sandy soils hold much less water and nutrients, so plants growing in them are more prone to drought and nutrient deficiency. One reason loamy soils are valuable is that they hold more water than sand, but they do not have the drainage problems of clays.Infiltration rate describes how fast water enters the soil surface. Infiltration is similar to hydraulic conductivity and largely dependent on it. Whenever you apply water to the soil surface at a higher rate than the infiltration rate, you will have puddling or runoff.Because clay soils often require short, light doses of water
to avoid runoff or puddling (and possess low hydraulic conductivity), they are more susceptible to salt buildup. This happens because each time you apply water, you also apply a small amount of dissolved salt along with it. In well-drained soils, you easily can apply enough water so that some of it drains, or leaches, completely through the root zone. This water takes some of the dissolved salt with it, thus reducing the amount to which plant roots are exposed. However, when infiltration rates limit you to small doses of water, you cannot apply enough to leach any out of the root zone. Thus, while water leaves the soil by evapotranspiration, the salt stays behind and slowly accumulates to toxic levels as additional irrigation water brings more. This also illustrates why water quality is an important issue.• Compaction and density. An aspect we have not touched on yet is soil-particle shape. Particles smaller than sand tend to be flattened and plate-like. This tendency is very strong with clay particles, and this has important implications. Clay particles, being flat, can stack tightly together, virtually eliminating any pore spaces between particles. In other words, porosity decreases. This is true with silts as well and is what happens when soils compact
and why compacted soils conduct little water or air. Further, root growth is reduced because pore spaces through which small roots grow do not exist in compacted soil. Moist soil is more prone to compaction because when ample water is present in the soil, the particles can slip and slide past one another, making repositioning into a more compact state easier.Clay particles also can seal, for the same reason. The flattened particles all can be oriented in the same positions—
flat—and form a barrier through which water and air cannot penetrate. That’s why it’s important to score glazed surfaces—such as those created by tree-spades in planting holes—to disrupt this barrier and allow water and air penetration. Sand tends not to compact because, unlike clays, sand particles are not flat. They cannot “stack” in a way that reduces pore space. That is why sand is the preferred medium for high-traffic turf such as golf greens and athletic fields—turf growing on sand is not as prone to the damage that compaction causes. At this point, we should mention pans. Pans are impermeable
layers present below the surface of some soils at varying depth. Hard pans are rock-like while clay pans are softer. Most pans occur naturally, but some cultural practices
can create them. For example, repeated core aeration at the same depth can create a pan layer of highly compacted
soil just below the depth of tine penetration.Pans all cause serious drainage problems in landscapes. They prevent water from draining and so create perched water tables. This not only saturates soil, it also causes salt buildup because salt cannot leach out of the soil. Even if you’re able to manage irrigation well enough to prevent these problems, pans still effectively create a “bottom” to the soil, which may be quite shallow. This can restrict the rooting depth of trees and shrubs.CHEMICAL PROPERTIESSoil chemistry is the interaction of various chemical constituents that takes place among soil particles and in the soil solution—the water retained by soil. The chemical interactions that occur in soil are highly complex, but understanding certain basic concepts will better help you manage turf and ornamentals.• Nutrition. Having discussed water relations, it now is a bit simpler to discuss nutrient-holding capacity. Soils hold onto nutritional elements in a way similar to how they retain water: Positively charged nutrient molecules, cations, are attracted to the negative charges on the soil particles. This is called adsorption. The sites where cations attach to particles are cation-exchange sites (see Figure 2, left). Thus, clay retains more nutrients than coarser soils, just as it holds more water, because of the greater surface area (greater number of cation-exchange sites) to which nutrients can adsorb. The ability to hold cation nutrients is called the cation-exchange capacity (CEC) and is an important characteristic of soils in that it relates to a soil’s ability to retain nutrients and prevent nutrient leaching. Coarse soils have low CECs, while clays and highly organic soils have high CECs. A sand may have a CEC of under 10—a Figure 2. This illustration shows plate-like clay particles. The negative (-) signs indicate negatively charged cation-exchange sites. Cation nutrients, as shown, adsorb to these sites. This is how clay soils act as reservoirs for nutrients.H+CA2+CA2+K+H+CA2+H+H+K+NA+NA+K+H+CA2+H+K+
2004 # TURF & LANDSCAPE DIGEST 11
very low figure. Any CEC above 50 is high, and such soils should be able to hold ample nutrients. • Salinity. Some soils, particularly in arid regions, hold high levels of salt. We discussed earlier how clay soils are more prone to salt buildup, and the same principle applies to arid-region soils. Low rainfall prevents leaching of salts, so they build up in soils. Pan layers, common in arid regions, further inhibit drainage and leaching. Some fertilizers and amendments also can increase salinity.• Soil pH. This is perhaps the single most important aspect of soil chemistry. Strictly speaking, soil pH, or reaction, is a measure of the number of hydrogen ions (H+) present in a solution. In more common terms, it is a measure of alkalinity and acidity. The pH scale runs from 0 to 14. Seven is neutral, 0 is the most highly acidic value possible, and 14 is the most alkaline, or basic, value. Most plants grow best in the range of 6.5 to 7.0, which is acidic, but only slightly. The so-called acid-loving plants prefer lower pH, in the range of 4.0 to 6.0. Under 4.0, few plants are able to survive. Slightly alkaline soil is not harmful to most plants (except acid lovers). In strongly alkaline soils, however, nutrient-availability problems related to pH result. The parent material of soils initially influences soil pH. For example, granite-based soils are acidic and limestone-based soils are alkaline. However, soil pH can change over time. Soils become acidic through natural processes as well as human activities. Rainfall and irrigation control the pH of most soils. In humid climates, such as the Northeastern United States, heavy rainfall percolates through the soil. When it does, it leaches basic ions such as calcium and magnesium and replaces them with acidic ions such as hydrogen and aluminum. In arid regions of the country (less than 20 inches of rain per year), soils tend to become alkaline. Rainfall is not heavy enough to leach basic ions from soils in these areas. Other natural processes that increase soil acidity include
root growth and decay of organic matter by soil microorganisms. Whereas the decay of organic matter gradually will increase acidity, adding sources of organic matter with high pH values (such as some manures and composts) can raise soil pH.Human activities that increase soil acidity include fertilization with ammonium-containing fertilizers and production of industrial by-products such as sulfur dioxide and nitric acid, which ultimately enter the soil via rainfall. Irrigating with water high in bicarbonates gradually increases soil pH and can lead to alkaline conditions.In most cases, changes in soil pH—whether natural processes or human activities cause them—occur slowly. This is due to the tremendous buffering capacity (resistance
to change in pH) of most mineral soils. An exception
to this is high-sand-content soils, where buffering tends to be low, as we’ll discuss below.Nutrient availability varies markedly according to pH. This, in fact, is the main reason why pH is so critical. The best pH for overall nutrient availability is around 6.5, which is one reason why this is an optimal pH for most plants.Calcium, magnesium and potassium are cation nutrients,
meaning they are available to plants in a form with a positive charge. As we discussed earlier, these nutrients adsorb to soil particles, especially clay particles. Soils high in clay or organic matter have high CECs. Thus, these soils act as reservoirs for these nutrients and plants growing in them seldom are deficient in the cation nutrients.Cations do not adsorb permanently to particles. Other compounds that are more strongly attracted to the cation-exchange sites can replace them. This is one way that pH affects nutrient availability. Low-pH soils, by definition, have many of their cation-exchange sites occupied by H+ ions. By default, exchange sites holding H+ ions cannot hold other cations. Therefore, low-pH soils are more likely to be deficient in nutrients such as magnesium, calcium or potassium. If cations are not held by particles, they can leach out of the soil.Soil-solution pH also affects the solubility of other nutrients in the soil. In fact, pH affects the availability of all nutrients one way or another (see Figure 3, above). Therefore, maintaining pH close to the ideal level—6.0 to 7.0 for most plants—is important.Buffering capacity is the ability of soil to resist changes in pH. Soils with a high buffering capacity require a great deal of amendment to alter pH. This is good if the soil already has a desirable pH, but it can be a problem if the soil needs pH modification. Normally, soils high in clay or organic matter (those that have high CECs) have high buffering capacities. Calcareous soils often have high Figure 3. The wider portions of the bars in this graph indicate pH ranges that favor availability of that nutrient. POTASSIUMSULPHURBORONCOPPER AND ZINC0 1 2 3 4 5 6 7 8 9 10 11 12 13 14NUTRIENT AVAILABILITY AND PHSoil pHNITROGENPHOSPHORUSCALCIUMMAGNESIUMIRONMANGANESEMOLYBDENUM
12 TURF & LANDSCAPE DIGEST # 2004 chapter 2
buffering capacities because lime effectively neutralizes acid—a great deal of acidification may be necessary to eliminate the lime before you can realize a significant drop in pH. Conversely, in lime-free soils, acid treatment can drop pH significantly. Soils also can resist upward changes in pH, depending on their composition. Because buffering capacity determines how much amendment it will take to change pH, this is an important characteristic. Soil labs determine buffering capacity and adjust their recommendations according to the buffer pH. AMENDING SOILSLandscape managers commonly manage soils to improve
their physical structure. Doing so entails cultivation and, often, the addition of some organic or inorganic amendment.One of the main reasons we amend and cultivate soil is to alleviate compaction (see “Testing for compaction—
bulk density,” below). Thus, it’s appropriate that this discussion should address preventing compaction as the first step in improving soil structure. Trees commonly suffer from construction activity, which compacts soil to an extent that often can kill the plant. On construction sites, create a zone around trees in which equipment is prohibited. In areas with high foot traffic, take steps to route people along paths that will not affect the root zones of existing ornamentals. The same thing applies to vehicular traffic. Other practices also help reduce or prevent compaction:Do not cultivate when the soil is wet. This can be a very frustrating situation during wet periods because it seemingly takes forever for soil—especially clay—to dry. However, cultivating soil when it’s wet will only destroy soil structure and cause the formation of blocky, hard clods impossible to break up. Keep traffic, including foot traffic, off of wet soil—soil compacts more easily when it’s wet. Improve drainage to speed soil drying and reduce saturation during wet periods. Apply mulch around trees, as far as the drip line if possible.
This will lessen compaction effects on the root zone and improve the soil environment for root growth.• Physical cultivation. Cultivation can take place in a variety of situations and by several means. The easiest and best time to perform cultivation is before the installation of the landscape or turf.If pan layers exist in your soil, now is the time to break them up, because it is nearly impossible to do so after the landscape is established. This may require some heavy-duty equipment but is well worth the trouble because pans can cause you no end of problems. Breaking a pan layer may require the use of a deep-ripper implement. If you cannot do this over the entire landscape, at least use augers or some other method of punching through the pan layer in your tree- and shrub-planting holes. Otherwise,
the plants will sit in a “bathtub.” If you must dig the planting hole deeper than you normally would to accomplish
this, do so. Just be sure to compact the backfill below the root ball to prevent too much settling. In established landscapes, cultivating soil is a more complex matter. To treat compaction problems around trees, several
options exist. Air injection and vertical mulching are techniques finding some use, but they have their drawbacks.
A treatment gaining in popularity that provides excellent results for trees growing in compacted soil is soil replacement with radial trenching. This involves digging a trench starting near the trunk and extending it outward to near the drip line. A recent study of this method used trenches that started 10 feet from the trunk of white oaks and radiated outward. The trenches were 10 feet long, 2 feet deep, 14 inches wide and held about 1 cubic yard. The trenches were refilled with amended soil rich in organic matter. These trenches reversed the decline of trees suffering from highly compacted urban soils by providing a favorable soil environment for the tree roots. Such trenches are easy to dig with a variety of equipment (or even by hand) and so represent a viable method of alleviating compaction around existing trees. Any digging around trees should avoid damaging major roots.Surface mulching around trees also is an effective method of improving soil conditions if the mulch covers
a large enough area. Mulch should extend to the drip line if possible. This produces results more slowly but is perhaps the best long-term strategy for alleviating compaction
around trees.Turf-soil amendment is a different matter. The most common method of cultivating turf soil is through core aeration. This method uses hollow tines that pull soil cores from the turf and deposit them on the surB
TESTING FOR COMPACTION—BULK DENSITYBulk density is a measure of compaction useful for comparing two or more samples from the same type of soil. (It is of little use with different
soil types.) Labs commonly express this value in grams of soil per cubic centimeter (cc).You can determine bulk density by using the excavation method. This involves digging a small hole. Remove the soil and place it on a piece of plastic to save for drying. Dry the soil in an oven for 24 hours at 220°F and then weigh it. The next step is to determine the volume of the hole you excavated. Do this by laying a thin plastic bag in the hole and filling it with water until the water level is flush with the soil surface. Note the volume of water that this requires. You now can determine the bulk density. Divide the weight of the soil by the volume of the hole. For instance 1,170 grams of soil divided by 750 cc (1 fluid ounce equals 29.5 cc) equals 1.56 grams per cc. Most soils fall into the range of 1.4 to 1.7 grams per cc. Values much higher than this may indicate a compaction problem.
face. The resulting holes, though they soon fill in with material, increase air and water penetration to the root zone. In many instances (low- to medium-traffic sites), doing this once or twice a year provides adequate relief from compaction. In high-traffic situations, such as golf courses and athletic fields, turf managers may core-aerate several times a year. Repeated coring at the same depth gradually can create a compacted soil layer. Deep-tine aeration, using much longer tines, reduces this problem. Drills or water jets also are aeration options that avoid the problem of compacted
layers. Many golf-course superintendents use a combination of these aeration techniques.• Amending soil. Cultivation techniques such as aeration help alleviate compaction created by traffic. Often, however,
soil has innate properties that make it difficult to manage. You can improve these soils with amendments that impart more desirable qualities to the soil.# Organic amendments benefit soils in several ways. They increase nutrient- and water-holding capacities and improve
drainage and aeration. In different ways, organic amendments benefit both coarse and fine soils. Because OM increases nutrient and water-holding capacity, it helps counter the drawbacks of sand-based soils. In clay soils, water and nutrient-holding capacities are not usually a concern. However, tilth (the quality that allows you easily to work a soil into a loose state), infiltration and drainage
often are poor in clay soils. These, too, benefit from organic matter, as already discussed. Organic amendments are available in many forms (see table, “Organic amendments,” above right), often as processed wood products. These amendments take some time to decompose to the point where they create actual humus, but they still provide infiltration, drainage and tilth in the meantime. Other common amendments include manure and peat.Wood-based amendments are infamous for their ability to tie up soil nitrogen. Obviously, this can be a problem and may require the addition of supplemental nitrogen to offset this loss. Manure can contain high salt levels, another problem that may be of concern in your situation. See Chapter 10 for more information on the effects of amendments on soil fertility. You will do no harm by adding large amounts of organic
amendments to soil. Thus, there is little danger of overdoing it. A more common problem is adding too little. Often, amounts greater than 50 percent by volume are necessary to achieve significant modification. If you feel you need a more precise idea of how much to add to achieve the desired changes, have a laboratory test your soil.# Inorganic amendments can be quite useful for improving soil quality. The main reason to amend soil with inorganic
amendments is to improve porosity and thus increase water and air permeability of the soil. Therefore, this discussion pertains mainly to clay soils. The best way to improve porosity with inorganic amendments is with coarse amendments. These consist of particles that range in size from sand to fine gravel. Smaller particles do not increase porosity enough to be useful as amendments. Coarse amendments should be of uniform particle size: amendments with a wide mix of particle sizes tend to pack tightly and reduce porosity rather than increase it. For amendments to be effective, the amendment particles
must bridge. That is, they must touch each other so that they create large pore spaces in between. This can require between 50 and 80 percent amendment by volume.
Small amounts of amendment are not very effective because they are too sparse to bridge with one another. Sand is the most commonly used inorganic amendment
due to its low cost and effectiveness. Calcined clay, perhaps most recognized as cat litter, is another effective coarse amendment that also increases CEC. Other amendments
that grounds-care professionals occasionally use include diatomite, zeolite, expanded shale, pumice, blast-furnace slag and sintered fly ash. The latter two materials
are by-products that are available on a regional basis. Perlite and vermiculite are materials used primarily in greenhouse and container culture but have disadvantages in landscape use due to their inability to remain intact under traffic.Gypsum (calcium sulfate) is an amendment professionals
often use to increase infiltration in some types of saline soils. Sodium in saline soils destroys good soil structure by causing clay particles to disperse. This dispersion effectively seals soil to water infiltration and percolation. Gypsum (and lime) displaces sodium, causing clay particles to aggregate (clump together) and create large pore spaces through which water can flow. The displaced sodium is then free to leach through the ORGANIC AMENDMENTSMaterialNitrogen tie-up*CommentsBark, compostedModerateLess nitrogen tie-up than raw bark.Bark, rawHighSevere nitrogen tie-up but improves porosity in heavy soils.CompostLowVariable. Qualities depends on material. Good amentment in all soil textures.ManureLowCan be high in salts.PeatModerateGood acidifier, but relatively
expensive.Rice hullsModerate to highInexpensive. Improves water retntion.SawdustHighSevers nitrogen tie-up. Avoid walnut.* Nitrogen tie-up provides some idications of whether you should add supplemental nitrogen if you use that amendment. High nitrogen tie up may requires you to add as much as 1 pound of nitrogen per 1,000 square feet to avoid nitrogen deficiency in the amended soil.
root zone (with enough water).Incorporating amendments—organic or inorganic—is simply a matter of tilling the material into the soil after
you’ve spread it on the surface. Don’t confuse the term amendment with mulch. Mulch refers to material that remains on the soil surface. Mulches can improve soil by reducing compaction, conserving moisture and decomposing
to increase OM in the surface layer of soil. However, by definition, they are not amendments.You can amend soil in existing turf by core aeration followed
by topdressing that you drag into coring holes. This type of soil replacement is not difficult but requires some time—perhaps a year or two depending on frequency of aeration—to achieve significant replacement of soil. # Topsoil. Many times, it is simply more efficient to bring in high-quality soil than to modify the poor soils already present on a site. Though this use of topsoil does not, strictly speaking, make it an amendment, the idea is the same: Provide a good soil environment for plant growth. Topsoil for sale often is actually loam. It may be of excellent quality, but it is a misnomer to call it topsoil. Of course, it is wise to inspect topsoil before purchasing it to ensure it’s of the quality you’re looking for. Ideally, the soil should be reasonably weed-free and should not contain too many large clods.If the difference between the topsoil and the site soil is great—as it usually is—till a shallow layer of the topsoil
into the top few inches of site soil. This will create a transition zone that will aid water movement and root growth between the two soils.CHANGING PHAfter improving porosity, changing pH is the most common reason for altering soils. Raising and lowering pH both are necessary at times, depending, of course, on the pH with which you’re starting.• Reducing acidity. Liming is the practice of applying an agent to reduce soil acidity (raise pH) and make soils more favorable for plant growth. The amount of lime you must add depends on the degree of soil acidity, the buffering capacity of the soil, the desired pH, and the quality and type of lime you use.# Liming materials. The most widely used liming materials
for turfgrass areas consist of carbonates of calcium or magnesium. These include ground, pelletized and flowable limestone. Of these three, ground limestone is the type used most widely. Crystalline calcium carbonate
(CaCO3), one type of ground limestone, is termed calcitic limestone. Dolomitic limestone, another ground-limestone product, comes from ground rock containing calcium-magnesium carbonate (CaMg[CO3]2) and has a higher neutralizing value than calcitic limestone. Dolomitic
limestone not only lowers pH but also can supply magnesium in soils that are deficient. Although ground limestone is the most inexpensive source, it is dusty and not as easy to spread as the pelletized form.Pelletized limestone is ground limestone (either calcitic or dolomitic) that has been aggregated into larger particles
to facilitate spreading and reduce dust. The pellets quickly disintegrate when wet.Flowable limestone is available for use on turf when you need to use a liquid application. Although liquid applications
are dust-free and uniform, you only can apply relatively small amounts at one time, and lime-spray suspensions may be abrasive to sprayer parts.Hydrated (slaked) lime [calcium hydroxide, Ca(OH)2] and burned lime (quicklime—calcium oxide, CaO) provide
a rapid pH change but can be phytotoxic. These products are corrosive and difficult to handle.As you might expect, sources of limestone vary in quality and effectiveness. Even two pelletized limestones made by different companies may vary in their ability to neutralize soil. To get the best bargain when purchasing lime products, look for quality, not just the lowest price. Two main factors govern the quality of a liming material: purity and fineness.# Purity. Most lime recommendations assume you will use liming materials that have the same neutralizing potential
as pure calcium carbonate. In other words, if your soil-test report recommends that you apply 50 pounds of limestone per 1,000 square feet, it assumes you will use a lime source that will raise soil pH to the same extent as 50 pounds of pure calcium carbonate at the same rate. A liming material with the same neutralizing potential as pure calcium carbonate has a calcium carbonate equivalent (CCE) of 100 percent.You should adjust the recommended rate of any liming
material with a CCE of less than or greater than 100 TCALCIUM CARBONATE EQUIVALENT (CCE) AND LIMING RATESTo adjust the lab-recommeneded liming rate for CCE, divide the recommended
liming rate by the CCE of the material you're using (most products state the CCE on their label). Then multiply by 100 to obtain the actual rate you should use. For example:75 pounds of limestone per 1,000 sq. ft. (the label-recommended rate) x 100 = 94 pounds of limestone80 (the CCE of the product) per 1, 000 square feetAs you can see, adjusting for CCE can make a significant difference in rates and helps ensure you are using adequate product to achieve the desired change in pH.
percent (see “CCE of liming materials,” above) so that you apply the right amount of material to raise your soil pH to the target level (see “Calcium carbonate equivalent [CCE] and liming rates,” page 14). Generally, because of impurities such as clay, the neutralizing value of most agricultural limestones is 90 to 98 percent. Most states require that agricultural liming materials state their CCE on the label. # Fineness. Any effective liming material should be finely ground. This is important because the rate at which limestone raises pH increases with the fineness of the particles. Plus, limestone affects only the small volume of soil surrounding each limestone particle. A given volume of limestone contains more particles if it is finely ground and thus affects more soil than coarser limestone. Many states govern the sizes of limestone particles in pelletized lime and agricultural ground limestone. Manufacturers usually print the actual range of particle sizes on the label. However, you will generally find little advantage in using material much finer than these minimum standards.# How and when to apply limestone. Lime will neutralize soil acidity and benefit turf growth faster if you incorporate
it directly into the soil. You can incorporate lime by spreading a layer on the soil surface following a rough grading, then mixing the lime 4 to 6 inches into the soil with rotary tilling equipment. Not only does this practice distribute the lime throughout the entire root zone, you can apply much more in a single application than with a surface application. Often, you can supply the entire lime requirement in a single application during establishment, whereas several surface applications may be necessary on established turf or landscape beds.A means of incorporating lime in established turf is through core aeration. If your soil-test report indicates that an area about to undergo renovation requires liming,
apply the recommended amount of lime (along with any needed phosphorus and potassium) after herbicide treatment and thatch removal, and just before or just after aeration. As you aerate and drag the area, some of the lime/soil mix will fall into the aeration holes and some will remain on the soil surface. The more vigorous
the aeration treatment the better the lime will mix with the soil. Established turfgrass areas should not receive more than 25 to 50 pounds of limestone per 1,000 square feet in any single surface application. If you use hydrated or burned lime, apply no more that 25 pounds per 1,000 square feet in a single application. The main reason for this is to ensure that a layer of excess residue does not remain on or near the surface after watering or, in the case of hydrated or burned lime, that plant injury does not occur. If a soil requires more limestone than you can apply at one time, use semiannual applications until you meet the requirement.Ground limestone sometimes is difficult to spread with conventional spreaders. However, pelletized limestone
spreads easily with conventional drop or broadcast spreaders. For large areas, commercial spreader trucks are available for custom spreading. You can apply ground limestone anytime during the year, but it is most effective in the fall or winter because rain, snow and frost heaving help work limestone into the soil.• Lowering soil pH—acidification. Soils often need acidification
in semiarid and arid regions or when you’ve applied excess lime. Plus, golf-course superintendents sometimes apply acidifying materials to their greens as a means of managing certain diseases. They accomplish this by applying ammonium-containing fertilizers such as ammonium sulfate or elemental sulfur, or by injecting sulfuric acid into their irrigation systems.Ammonium-containing fertilizers are effective for lowering
soil pH when you need only slight acidification over an extended period. In the Northeastern United States, some golf-course superintendents use ammonium sulfate to lower the pH of putting greens affected by take-all patch and summer patch diseases. While this practice is effective in some cases, take care to avoid foliar burn and over-stimulation of turf with nitrogen. To avoid burning, make the applications during cool weather (spring and fall) at low rates. When using this approach for disease management, you should monitor soil-pH levels frequently to avoid nutrition and thatch problems caused by low pH.If you require greater and more rapid acidification, you can use high-sulfur-content products. When you apply sulfur to soil, soil-borne bacteria convert it to sulfuric acid, thereby lowering soil pH. Powdered elemental sulfur
typically is yellow and fairly pure (greater than 90 percent sulfur). As with lime, sulfur is more effective in a finely ground state. Several sulfur products are available in powder form but, as such, are dusty and not easy to apply with spreaders. You also can obtain sulfur in pelletized
form (90 percent powdered sulfur and 10 percent bentonite clay). This is easy to spread with conventional fertilizer spreaders and quickly breaks down into the powdered form when moist. If you want to apply sulfur as a liquid, flowable forms also are available.The best time to apply sulfur is before establishment. By applying sulfur directly to the soil surface, and then tilling it into the soil, sulfur will be in direct contact with soil microbes and distributed throughout the CCE OF LIMING MATERIALS*MaterialNeutralizing valueBurned lime (quicklime)—CaO179Hydrated lime—Ca(OH)2136Dolomitic limestone—CaMg(CO3)2109Calcitic limestone—CaCO3100* These values are for the pure forms of these materials. Actual CCEs of the marketed materials is usually lower due to impurites such as clay.
Incorporating sulfurbefore planting also allows you to use greater amounts than possible with surface applications on established turf.Generally, sandy
soils require smaller amounts of sulfur to lower pH than mineral soils. For example, lowering the pH of a 6-inch-deep layer of sandy soil from 8.0 to 6.5 requires 27.5 pounds of sulfur per 1,000 square feet. However, a clay soil needs 45.9 pounds of sulfur per 1,000 square feet for the same adjustment.Established turf generally requires frequent applications
of sulfur at relatively low rates to lower pH. On putting greens, applications normally are around 0.5 pound sulfur per 1,000 square feet and should not exceed about 2.3 pounds per 1,000 square feet per year. You can double these rates on high-cut turf if you apply the product in cool weather. Remember, excessive sulfur can injure turf, especially in hot and humid weather.To determine if your sulfur applications are having the desired effect on pH, monitor your soil with laboratory tests. Make sure that you test the surface soil (upper 0.5 to 1 inch) separately because most of the sulfur you apply
to established turf will remain and react near the soil surface. This possibly can create highly acidic conditions in the top 0.5 to 1 inch of the soil.In recent years, some golf courses in the Southwestern United States have used sulfuric-acid irrigation-system injections to acidify soil. At least one system uses pH electrodes
and a computer to maintain water pH at a constant 6.5. If the pH falls outside the operating range, the system automatically shuts down. With innovations such as these, acidification of soils with acid injection undoubtedly will become more common in the near future.PH TESTINGYou can determine soil pH with one of several types of soil tests. However, not all soil tests provide accurate information about how much lime or acidifier you should apply. Test kits using dyes, pH pens or pH paper determine
pH rapidly in the field. The least accurate means of determining soil pH is with pH paper, but it can be useful in obtaining an approximate value. While each of these tests can provide a fair indication of soil pH and tell you if you need lime, they do not provide accurate information on how much lime you should apply. The table at left gives amounts of material needed to raise and lower pH. These figures are only approximate—consult a soil lab before undertaking pH modifications.Commercial and university testing labs accurately determine
pH values for soils over a range of pH values. They also provide meaningful lime recommendations for acid soils. They base their lime recommendation on a lime-requirement test that tells you how much lime is necessary to bring the soil to an optimum pH. The lime-requirement test takes the buffering capacity of a soil into account to provide buffer pH. Regarding pH amendments, buffer pH is more important than active pH.Each lab bases its lime recommendations on what they consider to be optimal pH for the turf or ornamentals you’re growing. Before submitting your soil samples, realize
that differences exist among labs regarding what they consider to be the optimum pH ranges for turfgrasses and ornamentals. This is why lime recommendations vary from one lab to another. The best way to deal with this problem is to choose a lab that provides recommendations that make sense to you and then stick with that lab for future testing to maintain consistency. TESTING, SAMPLING AND SOIL LABORATORIESSoil laboratories are necessary to provide accurate analysis
and meaningful recommendations. Many kits and test methods—some of which we mentioned earlier—are available that allow you to conduct crude analyses for various nutrients, as well as pH, texture, density and other factors. However, you should consider these only rough indicators of soil quality. A laboratory analysis is necessary for you to get a good grasp of your soil’s condition.For small landscapes, the cost of testing may not be justified unless serious problems are occurring. However, for larger landscapes and golf courses, the cost of testing is trivial compared to the benefits. The information labs provide allows you to take the appropriate management steps to maximize plant growth. Otherwise, you’re just guessing at how much and what type of material to apply if you wish to amend soils.The results from any kit or lab are only as good as the sample taken. Therefore, ensure that you follow instructions
on the soil-test form. Pay particular attention to the suggested number of subsamples per unit area, sampling pattern, sampling depth, mixing procedure and whether to include thatch as part of the sample. Take care not to contaminate the sample with fertilizer, lime or any other substance that may influence results.TLDRAISING SOIL PHPounds of ground or dolomitic limestone needed per 1,000 square feet to raise pH to 6.5.Starting pHSoil testure classSandLoamClay6.02035505.545751005.0651101504.580150200LOWERING SOIL PHPounds of elemental sulfur needed per 1,000 square feet to lower pH to 6.58.535 to 45N/A45 to 608.025 to 3535 to 507.510 to 1520 to 25
Grasses belong to one of the most evolutionarily advanced families of plants called Poaceae. The Poaceae family is subdivided into six subfamilies that include 25 tribes, 600 genera and 7,500 species. Nevertheless, only a few dozen species are suitable as turfgrasses because they must form uniform soil coverage and tolerate mowing and traffic associated with turf use. One key characteristic
of these grasses that makes them suitable as turfgrasses
is their compressed crown. This enables you to mow without cutting off the growing point and killing the plant. See “Taxonomy of turfgrasses” (page 20) for a list of grasses suitable for turf. Of the three subfamilies that turfgrasses fall into, the Festucoideae subfamily is comprised of cool-season turfgrasses,
and Panicoideae and Eragrostoideae include the warm-season turfgrasses. Differences in temperature-related turfgrass physiology, discussed in Chapter 1, primarily influence adaptation of the turfgrasses. Warm-season turfgrasses are best adapted to southern climates, and cool-season turfgrasses are best adapted to northern conditions (see Figure 1, below). Drought tolerance and avoidance also influence adaptation on non-irrigated sites. Because of these differences in adaptation, no one turfgrass
species will perform well in all locations. You must consider which species and cultivars are best for your particular location. Your local cooperative-extension service can supply you with a list of turfgrasses that are best adapted to your site conditions. Seed suppliers also can assist you in determining the best turfgrasses for your site. COOL-SEASON TURFGRASSES# Fescues. Fescues can be broadly divided by their leaf texture: fine-leaved fescues (creeping red fescue, sheep fescue, Chewings fescue and hard fescue) and tall fescue. Fine-leaved fescues are best adapted to well-drained, low-fertility, low-pH soil and shade. They do not take heat very well and do best when not overfertilized. You will see fine-leaved fescues in mixes with Kentucky bluegrass and perennial ryegrass in cooler climates and in mixes with perennial ryegrass for winter overseeding of warm-season turfgrasses. Of the fine-leaved fescues, only creeping
red fescue is rhizomatous. The rest are bunch grasses. Tall fescue is a relatively coarse-leaved, bunch-type turfgrass that is best adapted to the transitional climatic zone between North and South. Tall fescue is adapted to a wide range of soil conditions and, among cool-season species, tolerates heat and drought well. Because of its coarse-leaf texture, it is best planted alone without being mixed with other more narrow-leaved species. # Bluegrasses. Kentucky bluegrass is the most widely used turfgrass in cool, temperate regions. Its medium leaf texture and dark color make it an attractive turf for lawns. It is rhizomatous, a good sod-former and recuperates
well from injury. Kentucky bluegrass responds well Figure 1. Climatic zones of turfgrass adaptation.SOUTHERN ZONENORTHERN ZONETRANSITIONAL ZONE
o fertilization and will persist in transitional areas when irrigated. One concern of Kentucky bluegrass is its susceptibility
to summer patch, a lethal disease that is difficult
to control. Some cultivars are more resistant to summer patch than others. More than 100 cultivars of Kentucky bluegrass are available to consumers. These cultivars can differ dramatically in color, disease tolerance,
fertility requirement and shade tolerance. Because of this variability, it is extremely important to obtain local recommendations for the best cultivars for your site. Annual bluegrass is a light apple-green-colored blueChlorideae
Cynodon genus, bermudagrass
Buchloë genus, buffalograss
Bouteloua genus, gramagrass
Zoysia genus, zoysiagrass
mascarenegrassFestucoideae subfamilyAveneae tribe
Agrostis genus, bentgrasses
Phleum genus, timothy
common timothyTriticeae tribe
Agropyron genus, wheatgrasses
crested wheatgrassPoaceae familyEragrostoideae subfamilyTAXONOMY OF TURFGRASSESPaniceae tribe
Axonopus genus, carpetgrass
Paspalum genus, bahiagrass/paspalum
Pennisetum genus, kikuyugrass
Stenotaphrum genus, St. Augustinegrass
St. AugustinegrassPanicoideaesubfamilyAndropogoneae tribe
Eremochloa genus, centipedgrass
Festuca genus, fescues
F. rubra rubra
creeping red fescue
F. rubra commutata
Poa genus, bluegrasses
Lolium genus, ryegrasses
Bromus genus, bromegrasses
Cynosurus genus, dogtail
Puccinellia genus, alkaligrass
grass that seeds profusely at very low mowing heights. Primarily a bunch-type winter annual (one type is weakly stoloniferous and is more perennial), it tolerates low mowing and can quickly invade bentgrass greens. Because of its light-green color and the seed heads it produces, it can be a serious weed in bentgrass greens. Annual bluegrass is generally not planted intentionally but will naturally invade well-watered sites. It does not tolerate drought and is prone to many diseases. Because of its pernicious nature, turf managers often give up on keeping it out of turf and end up managing it as a desirable
species. Turfgrass breeders currently are developing commercially viable annual-bluegrass varieties.Rough bluegrass is another light apple-green-colored bluegrass. It is stoloniferous and well adapted to damp, fertile, shaded sites. Rough bluegrass has poor heat and drought tolerance. Because of its stoloniferous growth habit, it tends to segregate itself in patches if mixed with Kentucky bluegrass. Rough bluegrass tolerates cold temperatures
well and is used as an overseeded species in warm-season turfgrass stands. # Ryegrasses. Both perennial and annual ryegrasses are available for turf. Perennial ryegrass is a medium- textured
turfgrass adapted to moderate temperatures. It germinates quickly (within a week) and is most commonly
used as a nurse grass in mixes with slower growing
species such as Kentucky bluegrass and for winter-overseeding in warm-season species. It has good wear resistance, and, coupled with quick germination, it makes a good species for athletic-field turf mixes. One lethal disease that perennial ryegrass is particularly susceptible to is Pythium blight. Annual ryegrass is a cool-season, annual bunch grass with coarse-textured leaves. Although it germinates quickly and its seed is inexpensive, it does not persist. # Bentgrasses. Creeping bentgrass is a fine-textured stoloniferous turfgrass that tolerates low mowing heights. Its aggressive stoloniferous growth habit provides it with excellent recuperative potential but also makes it unsuitable
in mixtures with other species. Creeping bentgrass requires a high level of maintenance (fertility, mowing and disease control) to maintain it as a lawn. It is most used on golf-course greens, tees and fairways as well as tennis courts and bowling greens. Colonial bentgrass is fine-textured and sometimes has weak rhizomes and stolons. It can’t be mowed as short as creeping bentgrass but is suitable for fairway turf. Like creeping bentgrass, colonial bentgrass requires a high level of maintenance. Its poor heat tolerance limits its use to cooler, maritime climates. Velvet bentgrass is the finest-textured turfgrass we use. It is stoloniferous and lighter green in color and is especially
tolerant of shade and acidic soil. Because it has poor tolerance of heat and drought, it is only found in cooler maritime climates of the Northeast and Northwest. Redtop is a coarse-textured, rhizomatous bentgrass that was once used extensively in seed mixtures because of its rapid establishment rate. Unfortunately, redtop persists in newly established turf and, because of its coarse texture,
it is not compatible with fine- or medium-textured turfgrasses. Although not used for fine-turf areas, it is still used in some roadside utility mixes.WARM-SEASON TURFGRASSES# Bermudagrasses. Bermudagrass is the most important and widely adapted warm-season turfgrass. It is a highly variable turfgrass that produces aggressive rhizomes and stolons. Although primarily propagated vegetatively, improved seeded varieties are becoming available. Bermudagrass
thrives in warm, tropical and subtropical climates with moderate to heavy rainfall. Salt tolerance is high. Hybrids developed from crosses between C. dactylon
and C. transvaalensis for golf-course use include Tifgreen,
Tifdwarf and Tifway, and for home lawns, Midiron,
in areas that previously have been too cold for bermudagrass adaptation. # Buffalograss. Buffalograss is one of the few turfgrasses
native to the United Sates. Also unique about buffalograss among the turfgrasses is the fact that it has separate male and female plants. Buffalograss is a fine-textured, light green, stoloniferous grass that is well-adapted to unirrigated sites with low fertility. # Zoysiagrasses. Zoysiagrass is a stoloniferous and rhizomatous
species used for lawns and golf-course fairways in the South and the transition zone. It is not as aggressive as bermudagrass but forms a dense turf that is prone to thatch buildup. Zoysiagrass withstands cold temperatures better than other warm-season turfgrasses. Japanese lawngrass, a medium-textured turfgrass, is the most cold-tolerant zoysiagrass but, like all warm-season turfgrasses,
greens up relatively late in the spring and goes dormant
earlier in the fall than cool-season species. ManiTAXONOMY
OF KENTUCKY BLUEGRASS Kingdom—Plantae, plant kingdom Division—Anthophyta, flowering plants Class—Monocotyledoneae, monocots Subclass—Commelinidae, having chaffy flowers Order—Cyperales, grasses and sedges Family—Poaceae, grasses Tribe—Festuceae, fescue tribe Genus—Poa, bluegrasses Species—pratensis, having rhizomes Cultivar—‘Haga’
chapter 3lagrass is finer-textured but lacks the cold tolerance exhibited
by Japanese lawngrass. # St. Augustinegrass. St. Augustinegrass is a coarse-textured,
stoloniferous grass that is commonly used for lawns in coastal areas of the deep South. It has poor cold tolerance but tolerates moderate shade better than most warm-season turfgrasses. Salt tolerance is good with St. Augustinegrass, but it does not tolerate traffic or compacted
soil. Vegetative propagation is the only means of establishing this species. Several diseases are a problem with St. Augustinegrass. Perhaps the most serious problems are with brown patch, take-all patch and gray leaf spot. St. Augustine decline virus is another serious problem of St. Augustinegrass with no chemical controls available. Resistant varieties include Floratam, Seville and Raleigh. # Paspalums. Bahiagrass is coarse-textured and has short, almost woody rhizomes and stolons. It’s propagated
from seed or sod and is primarily used as a utility
grass on highway roadsides and low-maintenance lawns. It performs relatively well in poorly drained, low-fertility soils. Mole crickets are a serious problem in bahiagrass. Seashore paspalum is another species within the Paspalum genus. Its primary use is for its high salt tolerance.
# Carpetgrass. Carpetgrass is a coarse-textured, low-growing, stoloniferous grass that forms a dense turf capable of crowding out other species. This species is native to the Gulf states and is adapted to other tropical
areas. It’s primarily used on roadsides, airports, golf-course roughs and other utility-turf areas. Its frequent and prolonged production of seedheads is aesthetically objectionable and restricts its use to utility
turf. # Centipedegrass. Centipedegrass is a coarse-textured, slow-growing, stoloniferous species. It is established from sod, sprigs and seeding. It is a true low-maintenance turfgrass. Because of its slow growth, it requires less mowing than bermudagrass or St. Augustinegrass. It also performs well with only one annual application of nitrogen at 1 pound per 1,000 square feet. Traffic tolerance is poor, and it is unsuitable as an athletic-field turf. Centipedegrass typically has a natural yellow-green color and is used as a lawn and utility turf.
Turf Establishment and Renovation
Turfgrass maintenance problems often result from poor planning in the initial stages of establishment. Poor drainage, scalping and turf-susceptibility to environmental
stresses may be the consequence of poor establishment
techniques. To ensure a healthy turf and avoid later maintenance problems, begin with proper site preparation.The primary objectives of soil preparation are:• To provide a firm, smooth surface for rapid establishment
• To provide a rooting medium conducive to water infiltration,
aeration and drainage.The goal of proper site preparation is to create a firm foundation on which you can establish and maintain a high-quality turf with a minimum of difficulty.The steps for preparing the site are the same whether you establish turf by seed or vegetative methods.• Clear the site. Begin by removing any obstructions that may impede turf establishment and make future maintenance
difficult. These include rocks, boulders, old building foundations, roots of dead trees, brush and weeds. When planted over shallow rock outcrops, boulders
or old foundations, the turf will have a restricted root system, and it will continually suffer from drought stress. Either remove the obstructions or bury them at least 15 inches deep.Trees can excessively shade a site. This may prevent good turf establishment and lead to turf thinning. Trees also may reduce air circulation and create an environment
conducive to disease development. So selectively prune tree limbs to let in light and promote air movement
before establishing turf.Trees and turf also compete for nutrients and water. In some cases, you may have to remove trees that interfere with the turf and the site’s planned uses. If so, be sure to remove stumps. Don’t simply bury them. As they decompose,
the soil will sink. Eventually, a depression will form at the site. Fairy-ring disease also is likely to develop
on the excess organic debris. If you don’t remove difficult-to-control weeds from the site before establishment, you can expect serious persistent problems in the turf. Propagules—seeds, rhizomes,
stolons—let the weeds survive tillage and later infest turf. You’ll especially have problems from annual bluegrass seed, quackgrass rhizomes, bermudagrass stolons
and nutsedge nutlets.Non-selective, systemic herbicides or fumigants control
growing weeds and propagules. Choose materials that control all vegetation on the site yet have a short soil residual, allowing you to plant soon after treatment.Glyphosate is a non-selective systemic herbicide that the plant absorbs through its leaves then translocates to all other parts. To be sure that weeds have fully absorbed and translocated the herbicide to roots and propagules, it is best to wait a week after application before tilling the area. Soil microorganisms quickly deactivate glyphosate
once it comes in contact with the soil so you can plant soon after treatment.Fumigants are volatile materials that you apply to the soil in gaseous or liquid form. They kill all living organisms,
including seeds and other propagules in the upper layer of soil.• Test the soil. The best way to determine lime and fertilizer
requirements is with a soil test. By testing the soil, you can avoid spending unnecessary time, labor and money on materials that the soil doesn’t need. You also avoid applying excessive amounts of lime and nutrients, which could be detrimental to the future turf.• Rough grade and install drainage and irrigation systems.
Rough grading involves removing the topsoil and contouring the subgrade. By smoothing out surface irregularities,
such as steep slopes and depressions, you will greatly ease future maintenance. Steep slopes interfere
with mowing and make applying fertilizer and pesticides difficult. Irrigation also is difficult on slopes. Water often runs off before it can infiltrate the surface. If steep slopes face south, turf can suffer from heat and drought stress.When determining the contour, consider surface drainage. If the area will be heavily trafficked, such as an athletic field or golf course, contour the site so surface water can run off compacted areas. With athletic fields, add a l-foot crown in the center. Golf-course fairways, tees and greens should slope toward roughs. Home sites should slope away from the house to keep water out of basements.After contouring the subgrade, replace the topsoil, spreading it evenly over the site. Staking the area with markers showing the desired final elevation eases this operation. Topsoil settles after you spread it over the site. You can expect fine-textured soils to settle 5 to 10 percent.
Coarse-textured soils won’t settle as much. When marking the stakes, take this settling into account and mark them above the final settling level.
When filling areas with large amounts of topsoil, add the soil in 12-inch-deep layers, rolling between each one to speed settling. If the subsoil is considerably different than the topsoil, mix 2 inches of fill with 2 inches of subsoil to create a transition zone.Using soil amendments, modify topsoil that has a poor texture. Otherwise, the poor texture allows either compaction
or poor nutrient and water retention.Sandy soils don’t hold water or nutrients well. You can improve sandy soils by amending with organic materials or with calcined clay. These materials aid moisture retention
and increase cation-exchange capacity, minimizing nutrient loss. Organic amendments such as peat and compost work well.Because soil microbes break down organic matter, it is important to consider the stability of the material when choosing an organic amendment. Stable materials that resist decomposition will retain their soil-amending properties longer than materials that quickly decompose. The carbon:nitrogen ratio (C:N) is an indicator of the material’s stability. The higher the C:N ratio, the more stable the material. However, you must ensure the soil has adequate amounts of nitrogen when amending with material having a high C:N ratio. Microbes use nitrogen as they break down carbon components in the organic matter. The higher the C:N ratio, the more nitrogen it takes to break down the material. If soil nitrogen is low, the turf could become deficient.Peat is superior to other organic compounds because it is relatively stable and has a favorable C:N ratio. Reed-SEEDBED PREPARATION EQUIPMENTAA variety of seedbed-preparation equipment is available to help you get the job done on both large and small sites. Most are of three types: • Tow-behinds• Hitch-mounted units• Fast-mounting systems for frame-mounted attachments.Tow-behinds are attached to a draw bar that is bolted to a tractor frame. Hitch-mounted units use a tractor’s hydraulic 3-point-hitch system to lift them, so the operator controls the units’ functions and height. Fast-mounting systems usually take no more than 5 minutes to put in place.The following equipment types fall into these categories:# Rock pickers. You can rake top-side stones before planting, but it’s best to remove even small stones from the upper 4 inches of the root zone. These stones interfere with cultivation and damage machines. A stone-picking machine may handle the problem most effectively.Rock pickers are either ground- or PTO-driven and do a good job where rocks have been brought up to the surface. They operate best at 3 to 5 mph, and some models can pick rocks ranging from small stones to 200 pounders. Some can pick a ton of rock in 1 minute, so labor savings can be substantial.# Tractor rakes. Tractor rakes are especially efficient on stony or sandy soils. They remove trash and are particularly good for minimizing surface irregularities and contouring the subgrade.By angling these rakes, you can lay down windrows of rocks or trash for later pickup with trucks or front-end loaders. You also can add wheel and scarifier attachments for heavier soil.Soils in the West and Midwest often are too heavy for a tractor rake alone, so you may need to use a box scraper or scarifier/scraper on the area first. Many manufacturers make tractor rakes.# Rear scraper blades. Many of these blades, mounted on the rear of a tractor, include operator-activated tilt and angle controls. With the tractor in reverse, you can use the blade as a dozer. Rear blades use their own weight and the blade’s angle to dig.# Scarifiers. Two types of scarifiers handle different jobs. A scarifier/scraper uses teeth to rip up hard-packed soil while bringing stones to the surface. You can later drag the stones using the scraper blade. The scraper blade also roughly levels areas and spreads topsoil. On many units, you can easily switch the scarifier to the scraper by using a lever that rotates the unit.A scarifier/clod breaker works on level ground that hasn’t been finish-graded. The leading edge has fixed teeth that break up compacted
soil. A spiked roller bar follows and breaks clods turned up by the scarifier teeth. These units are best for light work and as preparation
for final hand raking.# Box scrapers. These attachments do an excellent job of breaking stones loose and leveling out an area’s high spots. Usually a welded brace keeps the box in a rigid position so the unit doesn’t rotate.Some box scrapers have a blade along the rear. The blade covers wheel tracks, while the box holds sand and soil being distributed over the area. Side shields on the blade trap scraped soil until the end of the pass, which controls soil placement. Optional scarifier teeth ahead of the blade can break up crusty soil.# Drags. A drag can be anything from a railroad tie to a large pipe to a heavy mat. Used for final smoothing, they’re usually hauled behind a tractor. Manufactured drags may have scarifier teeth, leveling bars or drag chains to smooth a surface. Drags are effective only on the soil’s surface.# Harrows. Some harrows look like chain-link fencing and are dragged behind a tractor. One side of a harrow has spikes that dig lightly into the soil. The other side is smooth and distributes soil side to side as it breaks up clods. It can remove light trash and cover seed, but it’s best use is for soil preparation.# Front-end loaders. Seedbed-preparation attachments for front-end loaders have a dual advantage. They can work the soil bed and lift loads, so debris can be put into a truck.Their hydraulic down-pressure can dig or make shallow passes to remove topsoil before grading. Front-wheel drive on many models is an additional advantage.
sedge peat is the most stable peat and is the preferred organic material for turf establishment. Add peat to the soil at the rate of 10 to 20 percent of the total volume of the mixture.You also can use coarse inorganic amendments for improving the structure of fine-textured, easily compacted
soils. Sand is the most widely used inorganic amendment. Another material that is good for this purpose
is calcined clay. Not only does it improve soil texture,
it also increases cation-exchange capacity and water retention. Calcined clay costs more to use than sand. Isolite is another inorganic amendment that shows promise. Research indicates that it improves aeration in heavy soils and aids water retention.Characteristics of a good coarse amendment include particle size, particle-size uniformity and durability of the material. The objective of using a coarse amendment is to create large pores in the soil. Sands that are too fine or that are composed of a wide range of particle sizes may actually impede water movement. Coarse amendments
that are not durable break up under traffic and lose their beneficial characteristics. For this reason, avoid materials such as vermiculite, perlite and diatomite.Because large pores are important in soil-water movement,
you must add enough coarse amendment that individual particles bridge, or touch, each other. The amendment may need to make up as much as 80 to 90 percent of the volume of the soil mixture. Have the soil and amendment physically tested by a university or commercial
soil-testing lab to determine the quality of the amendment and the native soil and to determine the amount of amendment to add.• Apply lime and fertilizer. Referring to soil-test results, incorporate any necessary materials 4 to 6 inches deep. In the absence of a soil test, you can apply fertilizer using standard recommendations. However, remember that you may be applying materials that aren’t needed, wasting
money and possibly creating detrimental conditions for the turf.Phosphorous is important to seedling rooting. Potassium
increases turfgrass resistance to stresses. Lime will correct an acid soil. Basic fertilizers, such as 10-10-10 and 0-20-20, supply phosphorous and potassium without adding excessive nitrogen. Because these materials are not mobile and don’t readily move in the soil, it is best to incorporate them into the soil before establishing the turf. Disk or rotary till them 4 to 6 inches deep following rough grading.• Finish grading. Finish grading will provide a smooth, firm seedbed free of obstructions. When the area has settled and the soil is moist—not too wet or too dry—it is ready for finish grading.Remove stones and other debris that may impede seedling emergence or interfere with future
If you have sufficient staff or the area is small, use hand rakes. Lightweight,
or wooden rakes with closely spaced tines are best for removing small stones and smoothing the soil.To achieve a smooth firm surface, it is best to rake then roll, alternating procedures until footprinting on the soil surface is minimal. A water-ballast roller one-half to three-fourths full is easy to push and is heavy enough to firm the soil.For larger areas, use a cultipacker to firm and smooth the soil.• Apply starter fertilizers. Starter fertilizers supply young, shallow-rooted seedlings with an initial source of nitrogen. A soluble nitrogen source is best because it is readily available to the seedlings. If you didn’t incorporate
fertilizer in the soil during site preparation, you should use a complete fertilizer at this time.Apply starter fertilizer just before seeding or as you seed. Lightly rake the fertilizer into the upper 0.5 inch of the soil surface. Use 1 to l.5 pounds of nitrogen per 1,000 square feet. If the turf doesn’t sufficiently grow or green up, you can supplement the initial application with 0.5 pound of nitrogen per 1,000 square feet when the seedlings reach 1.5 to 2 inches in height. BUY HIGH-QUALITY SEEDHigh-quality turf starts with high-quality seed. High-quality seed is one of the most important prerequisites
for the establishment of a persistent, weed-free, high-quality turf. Poor-quality seed may be contaminated
with weed seed and undesirable turf species or varieties. It may have low purity and germination percentages.
Using poor-quality seed can lead to persistent maintenance problems in the future and can waste all the time, effort and money you spend on soil preparation,
fertilization, liming and seeding.Because turfgrass species and varieties are adapted to different environmental conditions, have varying levels of disease susceptibility and perform differently under varying levels of cultural intensity, it always is best to refer to local recommendations from county or state extension specialists.# Identifying seed. Botanically speaking, the turfgrass seed is a caryopsis. It is composed of an embryo, endoCaryopsis
PaleaLemmaTesta (seed coat).
sperm and the testa, or seed coat, which is fused to the ovary wall. The embryo is a rudimentary plant, and the endosperm provides energy reserves, allowing the embryo
to grow until it can manufacture its own food by photosynthesis.The turfgrass seed is not strictly a true seed. It is actually
a floret. The floret includes the caryopsis enclosed by two floral bracts called the palea and the lemma (see Figure 1, page 23). At the base of the palea is a stem-like structure
called the rachilla.The seed of most major turfgrass species is easily identifiable
through distinguishing marks on the seed. For example, seed size, shape, color, pubescence, awns, the number of nerves or veins running lengthwise on the lemma, and the shape of the rachilla can help you identify
the species making up a turfgrass blend.Seeds of species within the genera Agrostis (bentgrasses),
Poa (bluegrasses) and Festuca (fescues) are similar. So while you can identify the genus, you can’t easily tell the species in a mix. You won’t know if you have Kentucky bluegrass or rough bluegrass, hard fescue or red fescue. It’s also extremely difficult to distinguish among the varieties of a particular species.It is important to note that every rule has an exception. Seed harvesting, cleaning and packaging procedures can damage the distinguishing features of a seed. Thus, it’s best to look at several specimens before making a positive
identification.# Labeling seed. Regulatory agencies on the federal and state levels monitor the seed industry and enforce standards
for seed quality. The Federal Seed Act of 1939 regulates the sale, transportation and distribution of seed imported into the United States and seed that is transported
across state lines. Individual states also have seed laws. Although seed laws vary from state to state, they all require that seed packages have a label attached and that their contents meet basic minimum-quality requirements.
Although all seed must bear a label, the label alone doesn’t guarantee the varietal purity of the seed in the package. Seed regulatory agencies inspect seed during production and after harvest, mixing and packaging. Seed that meets the specifications of the state agency receive an official certification tag—a guarantee of varietal
purity.Specifications differ from state to state, and seed that is certified in one state may not necessarily meet the certification specifications of another state. In addition, certification doesn’t guarantee the other components of seed quality on the label: purity or germination percentage.
The seed label must provide some basic information. With this information, you can tell what turfgrasses you are buying and the proportion of each species in the bag. Information on the bag should include:• Name and address of the labeler• Lot number• Whether the turfgrass is fine- or coarse-textured• The turf species and varieties listed in order, starting with the variety making up the largest portion of the mix• The percent by weight of pure seed for each species and variety—the purity percentage (pure seed is the named species minus the amount of weed seed, inert matter, chaff and other crop seed)• The germination percentage or percentage of viable seed• Percent of other crop seed by weight• Percent by weight of weed seed, including that of restricted
noxious weeds• Percent of inert matter by weight• Number of restricted noxious weed seeds per ounce or pound• Date on which the germination test was conducted.The germination percentage that is listed on a label for a particular turfgrass seed reflects the germination capacity
of the seed. Germination percentages are calculated from the number of seeds that germinate in a test sample. TEMPERATURES FOR SEED GERMINATIONThe optimum temperature for seed germination alternates between
two significantly different temperatures—a reflection of what occurs naturally in spring and fall. The first temperature
lasts about 16 hours and the second for about 8 hours. For cool-season turfgrasses, the optimum day temperature for seed germination is higher than that of shoot growth. As a result, the ideal strategy is to plant in late summer. At that time, soil temperatures are optimum for germination, but they soon afterward
fall to the range optimum for shoot growth. The optimum soil temperature for root growth of cool-season species is 50°F to 65°F. Thus, late summer or early fall planting also benefits root growth.For grasses that spread by tillers, you can use less than the recommended seeding rate, but it will take more time for the turf to achieve complete coverage.For bunch-type species, such as fescues and ryegrasses, it is particularly important to use the suggested seeding rate. These species don’t spread to fill in voids between plants.Using a higher seeding rate than suggested will not achieve more rapid turf formation. Excessive seeding rates lead to an increased number of individual plants per area, but the stand is composed of spindly plants that are slow to form a mature turf. The plants remain in a juvenile state, which impairs lateral shoot development and sod formation.
Seed companies conduct germination tests on a seed lot every 9 months, and that date must be listed on the label.
Although companies take measures to reduce the amount of contaminants in a seed lot, contamination can occur. Inert matter is the percent by weight of any material
in the seed lot that will not grow. It may include chaff, small stones, sand, pieces of seed, asphalt or other bulking agents. The cleaning process normally reduces the amount of inert matter. However, companies sometimes
intentionally add it to “bulk up” the seed lot, making
less-expensive seed.There are two basic weed-seed categories: noxious and non-noxious. Noxious weeds are ones that, when established,
are objectionable and difficult to control through normal practices. You can further divide noxious weeds into prohibited and restricted weeds. Prohibited noxious weeds are exceptionally difficult to control, and laws ban their inclusion in seed mixes. Restricted noxious weeds are permitted in turfgrass seed lots, but at specified low amounts. Weed problems differ across the country, and states have established their own lists of prohibited and restricted noxious weeds.The label must state both the kind of noxious weeds and the number of weed seeds per pound. The label must also include a percentage by weight of all weed seed—noxious and non-noxious—present in the seed lot.The label also must list any seed considered a crop seed that is in the seed lot in amounts greater than 5 percent of the mix. When crop seed makes up less than 5 percent of the mix, it will be listed in a general “other crop seed” category. All other crop seeds will be combined as a total percentage of the seed lot by weight.In some cases, crop seed can cause serious, persistent problems for the future turf stand. Annual grasses and most broadleaf weeds are easily controllable. But it’s hard to control perennial grasses without killing the turf. Bentgrass, tall fescue, rough bluegrass and orchardgrass are crop seeds that are not compatible with Kentucky bluegrass. Even when present in amounts of less than 5 percent, such grasses will seriously detract from the quality of a Kentucky bluegrass turf.# Seed calculations. See “Appendix: Turf and Landscape Calculations” for seed calculations concerning seeding rate and pure-live seed, and determining the best buy for seed.SEED APPLICATIONSeeding is the least expensive and least labor-intensive means of propagating turfgrass. And it is the way most cool-season turfgrass species are established.The best time to seed cool-season turfgrasses is in fall. You can seed in spring, but summer annual weeds, such as crabgrass, compete with and often overrun the emerging
turfgrass seedlings. Also, summer weather can stress seedlings, causing stand losses.When sowing seed, strive to evenly distribute it over the seedbed at the proper rate and provide good seed-to-soil contact. Several types of seeders are available to help you meet these goals. You can seed by hand, but it requires considerable skill and is not practical for large sites.• Broadcast spreaders are appropriate for small or moderately sized areas. You can cover a wider area with these spreaders than you can with drop spreaders. However, wind can deflect seed coming out of broadcast spreaders, making it difficult to get a uniform distribution. Also they may not evenly distribute mixtures, as different-
sized seed can spin out at different rates. Be careful when seeding the boundaries of an area to ensure seed doesn’t go beyond the area, thus wasting seed.• Drop-type spreaders deliver seed through holes in the base of a hopper. The hopper has an agitator that helps force seed out of the holes. Seed placement is more accurate with drop spreaders than with broadcast spreaders. Wind is less of a problem. But it is easy to skip areas between application strips and to excessively overlap strips. The best use for drop spreaders is in small areas and along borders where you need accurate seed placement.• Disk-type seeders have vertical blades that cut slits in the soil. Seed drops into the grooves from a hopper behind the blades. Disk seeders place seed in direct contact with soil so more seed germinates with these types of seeders than with drop or broadcast seeders. You normally use lower seeding rates with disk seeders than you use with broadcast spreaders.• Cultipacker seeders are tractor-mounted units that not only uniformly distribute seed but also firm the seedbed after planting. The roller component is ridged to ensure proper seed placement. This equipment is appropriate for seeding large areas.• Hydraulic seeders are essentially large-capacity sprayers with a single-nozzle delivery system. Through them, you can apply a mix of seed, mulch, fertilizer and other materials to slopes and areas where other seeding methods
are impractical. Because this method doesn’t provide good seed-to-soil contact, it is critical that you mulch hydraulically seeded areas.# Uniform application. To ensure uniform application, make two passes over a site, the second one at right angles
to the first. In this way, you can cover any skips you make with the first pass. Calibrate the spreader to deliver
one-half the recommended seeding rate in each pass.# Seed-to-soil contact. If establishment is to occur, seed must be kept moist and have a place to anchor its
roots. Thus, good seed-to-soil contact is important for germination. Good seed-to-soil contact also prevents seed from drying too quickly and enables seedlings to root into soil more rapidly.With broadcast and drop spreaders, you should lightly rake the seed into the upper 0.25 inch of soil then roll to firm the soil. You don’t need to do this with disk seeders
or cultipacker seeders because they work seed into the soil as they go.# Mulching. Mulch helps provide a favorable environment
for germination and seedling development. It reduces
moisture loss while seed germinates and begins to grow and shades seedlings, minimizing daily temperature
increases. Mulch also helps stabilize the soil until seedlings have rooted.Many different mulches are available from which to choose. Straw mulch is most popular. It is easily obtainable
and inexpensive. Take care to ensure that the straw is free of weed-seed, or you could have future weed problems.Apply straw by hand or with a mechanical blower. Evenly distribute it to get 50-percent soil coverage—1 bale per 1,000 square feet or 1.5 to 2 tons per acre.Generally, you can leave straw mulch on the seedling stand because it will decompose in a relatively short time.Wind often blows straw mulch. Tie it down with twine, crisscrossed over the site and staked down. Asphalt
binder is often used to stabilize mulch on large areas. Apply it at the rate of 200 gallons per acre.Wood mulches such as wood cellulose fiber, wood shavings or excelsior are comparable to straw. Other wood mulches—sawdust, wood chips or bark mulch—can upset the soil C:N ratio and tie up much of the nitrogen
in the soil. These materials also do a poor job of modifying the seedling microclimate.Apply wood cellulose fiber by hand or as a slurry through a hydraulic seeder. You can buy excelsior in 4-foot-wide rolls or as a loose material. Apply it by hand or with a mechanical mulching machine.Burlap, cheesecloth, jute netting or tobacco shade cloth are good mulches for slopes or other critical areas, such as in drainage swales or around irrigation heads. When laid out and staked along a slope or drainage swale, they effectively stabilize seed and minimize moisture loss. These materials are biodegradable, so you can leave them to decompose on the site.Elastomeric polymer emulsions form a thin rubbery layer over the seedbed. When you apply these materials in a low-pressure stream of water using a 9:1 proportioner,
seed stabilization is good. With these materials, you judge the application rate by how well they cover the site. Be careful not to apply too much material as it could seal the surface and impede seedling germination.# Aftercare. Because seedling turf is much more sensitive
than mature turf, you must manage it differently. Seedlings don’t have the extensive root system of mature turf and can’t easily obtain water and nutrients. They are also more susceptible than mature turf to injury from disease, environmental stresses and herbicides.Proper irrigation is the most important management practice following seeding. If you don’t supply water once the seedlings begin germinating, the stand will be lost. Keep the upper 0.5 inch of soil moist during establishment.
Irrigate lightly and frequently until the turf matures. If you haven’t mulched the area, water several times during the day to prevent drying.Excessive watering can be as damaging as infrequent watering, especially during warm weather. Pythium blight is a fungal disease that is active when warm, moist or humid conditions prevail. It is particularly lethal to seedling turf and turf that is succulent from excess nitrogen.
The care you give young turf—frequent irrigation
and starter fertilizer—promotes perfect conditions for the development of Pythium blight.Other diseases can attack seedling turf, including damping off, root rot and seed rot. These can kill plants before or right after they emerge. Thiram or captan will reduce injury from damping-off organisms.Mow the seedling stand when its height is one-third greater than the recommended mowing height for the species. For example, you normally maintain tall fescue at 2 to 4 inches high. So when seedlings are between 2.7 and 5.3 inches, mow them to the recommended height.An exception to the rule is close-cut creeping bentgrass.
Begin mowing it at 0.5 inch, then gradually lower the cutting height as the turf matures.Take care not to uproot seedlings with the first couple of mowings. A well-sharpened mower blade can help here. To avoid making ruts in the seedbed, use a lightweight
mower. Or mow only when the seedbed is relatively
dry and firm.Apply nitrogen fertilizer 3 to 4 weeks after seedlings have emerged and have grown to 1 to 2 inches tall. Apply
soluble nitrogen at 0.5 pound actual nitrogen per 1,000 square feet. If you use slowly available nitrogen, use a rate of 1 pound per 1,000 square feet.Herbicides that you can use on mature turf may damage
seedlings. This is why it is so important to control as many weeds as possible before you establish the turf. Most herbicides require you to hold off on treatment until the turf has been mowed two to three times. Others
have a much longer waiting period. Siduron is the only pre-emergence crabgrass herbicide that you can apply before seeding. Before applying any herbicide to
new turf, read the label carefully. SOD INSTALLATIONA sodded area can be no better than the quality of the starting product. If sod is certified in your state, purchase
certified sod containing varieties well-adapted to your area. A scheduled visit to prospective suppliers’ fields will acquaint you with growers and the quality of sod they produce long before you take delivery. Make sure your supplier does the following things before harvesting the sod:• Maintains a uniform cut at appropriate heights for the individual turfgrass species.• Allows no more than 0.5- inch of uncompressed thatch. To reduce the potential for heat buildup in stacked sod (which can lead to transplant failure), make sure the grower removes excessive clippings.• Applies 0.25 to 0.75 pound of actual nitrogen per 1,000 square feet to improve color. (Avoid excessively fertilized sod, as indicated
by dark-green, lush leaves. Sod fertilized with excessive nitrogen in particular leads to stress-susceptible turf with poor rooting potential. Sod in this condition has a greater tendency to heat on the pallet and is more susceptible to transplant failure.)Although sod pieces come in various sizes, make sure the width does not vary by more than 0.5 inch to ensure installation ease and a uniform initial appearance. Make sure the sod is 1- to 0.75-inch thick, excluding thatch and leaf length. Thickly cut sod—1.5- to 2-inches thick—is sometimes used on specialty-use turf areas, such as athletic fields, to shorten the waiting time before the area is usable. However, for most turfgrass areas, thinly cut sod is easier to handle and roots more readily.
Test for sod strength by holding the sod by one end and observing whether it tears or loses its shape. Sod that falls apart easily may have been harvested too young or managed poorly. It is difficult to install and a high risk for successful establishment.# Soil preparation. Sod often fails to establish or perform
well because no one bothered to correct deficiencies
in the physical and chemical condition of the soil. Prepare soil as you would for a seedbed by first sending a soil sample for analysis by a reputable testing laboratory.
This will help determine the amounts of nutrients needed to correct deficiencies. Also, follow the laboratory’s
recommendations for correcting an acid or alkaline soil to pH 6.0 to 7.0.When renovating existing turf, remove the old grass below the thatch layer rather than tilling it in. Treat difficult-
to-control weeds with appropriate herbicides before
adding amendments. To improve the water-retention properties and soil structure of sandy or heavy clay soils, add about 30 cubic feet of peat moss per 1,000 square feet. Apply 1 to 2 pounds of actual nitrogen per 1,000 square feet. Apply fertilizer, lime or other amendments recommended by the soil test, incorporating all amendments
at least 6 inches into the soil. Rake the soil to a smooth, level finished grade and roll it to provide a firm planting bed.Where high-quality topsoil is difficult to obtain or economically prohibitive, incorporate sand and organic matter to improve existing soil conditions.# Schedule operations. Schedule operations carefully and complete all soil preparation before sod delivery. Install sod immediately after delivery—within 12 hours of harvest in warm weather and 36 hours during cool weather. Yellow leaves and signs of mold and mildew indicate that the sod remained on pallets or stacks too long, has reduced vigor and will establish poorly. Do not accept sod that arrives on site in this condition.# Supply adequate moisture. Sod is living turf with a limited root system, so make sure the sod remains moist until a new root system develops. Water the soil lightly before you install the sod, or schedule soil preparation so the soil is still moist when you install it. For high-quality turf, you cannot get away with irrigating only after installation.Irrigate again within 20 to 30 minutes of installing the first piece of sod. Thorough irrigation to a 6-inch depth immediately after installation should help maintain adequately
moist sod.Make sure all sod pieces are butted together tightly and do not overlap. Stagger the joints in each row the same way bricks are laid and use wooden stakes to hold sod in place on steep slopes. Roll sod to smooth the surface and to bring the bottom of the sod layer into intimate contact with the soil surface.Until the root system begins to develop, irrigate often enough to keep the sod pad moist; this usually means irrigating 0.25 inch per day for the first week after installation.
After a sufficient root system develops, reduce irrigation frequency and irrigate to a depth of 4 to 6 inches every 5 to 10 days.Bermudagrass sod may root sufficiently within 3 to 5 days and quickly allow a reduction in irrigation frequency.
However, Kentucky-bluegrass sod requires careful
irrigation for 2 to 3 weeks to become successfully established during summer-stress periods. Mow the newly sodded area when the turf exhibits a 30- to 50-percent increase in vertical-shoot growth. For example, if you maintained the sod at a 2-inch cutting height before harvest, you should mow for the first time when the grass reaches a height of 2.75 to 3 inches.Apply 0.5 to 1 pound of nitrogen per 1,000 square feet after 4 to 6 weeks if the grass begins to show signs of
chapter 4nitrogen deficiency. Use lower rates during summer on cool-season grasses and higher rates during more favorable
seasons. Use the higher nitrogen rate on warm-season
turf.A common practice on construction sites is to remove topsoil and haul it off-site. This practice brings heavy clay soils or soils with poor chemical characteristics to the surface. Before starting to establish sod, bring in a high-quality topsoil free of viable weed seeds, rhizomes or other propagative parts to replace what was removed.
Establish a subgrade with the existing soil material and adjust the upper 3 to 6 inches of the subgrade to a pH between 6.0 and 7.0. Grade and firm the subsoil to approximate
the final contour and slope. Make sure you have adequate surface drainage and, if necessary, install subsurface drain lines within the subgrade to ensure proper drainage. Spread enough high-quality topsoil to cover the subgrade at least 4 inches deep. Till it into the upper 2 to 3 inches of subsoil to prevent distinct layering between topsoil and subsoil.Correct any mineral nutrient deficiencies and adjust pH of the topsoil following the recommendations of a soil-testing laboratory. Establish the final grade. Smooth and firm the planting bed. Install your sod.RENOVATION# Correct pH, salinity or sodic soil problems. Once you make the decision to renovate a lawn, submit representative soil samples to a reputable soil testing laboratory 3 to 4 weeks before you need results. The soil test will indicate whether the soil is acidic or alkaline, an important consideration
because pH could have contributed to the original deterioration. Soil with a pH below 6.0 needs lime; alkaline soil with a pH above 7.4 needs an acidifying
material such as sulfur. The soil test will indicate the specific rate of lime or acidifying material to apply. Correct
soil pH at the time of soil cultivation, so the liming or acidifying material will move deeper into the soil.# Eradicate undesirable species/weeds. Whenever possible, renovate existing lawns by applying fertilizer and broadleaf
and pre-emergence herbicides that won’t inhibit seedling development, then overseed with improved varieties. If the lawn is badly contaminated with perennial
weedy grasses or poorly adapted species, it is better to kill the existing grasses and re-establish a completely new lawn. Schedule herbicide applications for control of undesirable weedy species at least 3 to 4 weeks before you plan to plant unless the product label contains other instructions.# Remove heavy thatch. A certain amount of dead organic material enhances soil-moisture retention, but a layer of thatch 0.5-inch or more thick may contribute to turf deterioration. Vertical cut to remove excessive thatch or dead vegetation resulting from the herbicide application. Make multiple passes in varying directions to remove most of the thatch and dead vegetation.# Fertilize based on soil tests.# Cultivate to loosen compacted soil. Sites with excessive soil compaction may need turf cultivation, usually accomplished
by coring or slicing. Again, you may need to make multiple passes over the area to achieve the desired degree of soil loosening. Following coring, immediately drag the area with a mat or similar device to break up the cores and redistribute the soil over the surface.When seeding into bare soil, the seedbed is the right firmness and ready for seeding when a footprint leaves a 0.25-inch depression.# Scalp just before seeding to reduce competition from existing vegetation.# Seed. Depending on the size of the area, use a drop-type spreader, a rotary-type spreader, a slit seeder—which combines soil preparation and seeding in one step—or a hydraulic seeder.If you select a spreader or seeder, spread half of the total seed in one direction over the entire surface; apply the second half at a right angle to the first to ensure even application. After seeding, lightly drag a mat over the area to work the seed into the top 0.25 inch of soil.The speed of establishment varies according to the time of year and watering efficiency. In late summer on warm soils, perennial ryegrass may germinate in 5 days. Fine fescue and tall fescue may appear in 7 days and Kentucky bluegrass in 10. During early spring on cold, wet soils, establishment may take two or three times longer than in summer.# Irrigate daily for 2 to 3 weeks. The first irrigation should wet the soil to 6 or 8 inches without washing out the seed. Subsequent watering should dampen the surface whenever it has dried, which may be two to three times daily in hot weather. If you can irrigate only once a day, do so at midday. POST-GERMINATION CARE# Mowing. You can mow perennial ryegrass in as little as 3 weeks after seeding. Kentucky bluegrass may be ready to cut in 6 weeks. New turf is ready for mowing when it grows taller than the cutting height planned for the new turf. Follow the normal mowing practice of not removing more than one-third of the leaf area at any one mowing.# Herbicides. Cultivated farm soil averages 5,000 weed seeds per square foot, and the typical topsoil in a lawn probably has even more. Fortunately, most weeds can’t tolerate mowing and quickly die. In general, turf that has been mowed at least twice tolerates broadleaf-herbicide
Tree & Shrub Establishment
In many parts of the country, fall is promoted as a good time to plant trees and shrubs. Although this is true, the timing of tree and shrub planting is not as critical as using the proper planting techniques. Many people joke that all you need to do is dig a hole and position the plant green side up. On the contrary, research
over the past 20 years shows that the planting process is far more sophisticated than that if you want to be confident of planting success.Professionals may plant almost any time of the year, depending on the region. However, winter may be impractical due to frozen ground, and summer places heavy water demands on the transplant, requiring extra attention to irrigation. Thus, spring and fall are the preferred times to transplant due to the moderate weather during these seasons.PLANTING HOLE PREPARATIONTrees and shrubs require similar planting procedures.
For trees, dig shallow planting holes that are two to three times as wide as the root ball or root spread. For shrubs, dig similar holes. Another option is to rotary till the entire shrub planting bed, then dig holes slightly larger than the root balls or root spread. Wide, shallow holes encourage the horizontal root growth that trees and shrubs normally produce.Planting-hole depth depends on the drainage conditions.
In well-drained soils, dig holes as deep as the root balls. In poorly drained soils, dig holes 1 to 2 inches shallower than the root balls, covering the exposed root-ball tops with mulch.Do not dig planting holes any deeper than the root-ball depths. Otherwise, you will have to put soil back into the hole beneath the root balls. Loose soil will compact over time. Your trees and shrubs then will sink, causing them to be planted too deeply. In addition,
slow-draining water from the bottom of the planting hole can damage their roots.Whenever possible, you should widen the tops of your planting holes. Doing so will increase the well-aerated soil area near the surface where most root growth occurs. Also, take time to score walls of machine-dug holes to eliminate glazing, particularly in clay soils.TREE AND SHRUB PREPARATIONPlacing the plant in the planting hole is simple for container-grown or bare-root specimens. For larger specimens, such as B&B or box trees, it is a bit more demanding. Use anything that will allow you to lower the root ball into the hole without disturbing the roots. It is tempting to use the trunk, but this risks other harm to the tree. Instead, use ropes to lower the root ball into the hole or boards on which you can slide the root ball. If the tree comes in a wire basket, use the wire hoops as grips. Heavy, large specimens may require a small crane or hoist.The wrapping material around a root ball, or the container in which it has grown, can cause problems.
Growers often use synthetic materials that don’t degrade or treated burlap that degrades slowly. In addition, the ropes that tie or lash the balls are often non-degradable materials. With B&B trees and shrubs, inspect the wrapping materials around root balls and cut or remove any non-degradable material. However, do so only after the tree is situated in its final position within the planting hole. Other factors to consider are:• Ball-pinning nails and ropes. Cut away as much wrapping material as possible, or drop the wrapping material to Figure 1. When planting bare-root plants, construct a cone of soil in the planting hole and spread the roots out over it. Use a board over the planting hole to find the proper planting level.
the bottom of the planting hole, eventually backfilling
over it.• Wire baskets. These can be a problem because they rust away slowly underground. To keep equipment from being caught in the top loops during future landscaping—
and to keep surface roots from girdling—cut 8 to 12 inches off the top of all baskets.• Plastic containers. Remove all plastic containers. If available,
select trees grown in containers with vertical ribs or copper-treated interior walls. These types of containers minimize circling roots.• Fiber pots. Break away the top portion of the pot or remove the pot entirely from trees and shrubs. Many fiber pots are coated or compressed to extend their shelf life, but such techniques slow degradation below ground and retard root extension.• Root pruning. Cut dead, diseased or broken roots back to healthy tissue. Also, either remove or straighten circling roots or those matted in the bottom of the container. Planting is the time to eliminate roots that might cause girdling later on.Straightening some of the per-ipheral roots so they extend a few inches into the backfill will aid the plant’s establishment. These roots will grow more easily than those that must grow out of an undisturbed
root ball.When you plant bare-root specimens, build a cone of soil in the bottom of the planting hole. Then spread the roots out over the soil cone (see Figure 1, page 29). FINISHING PLANTINGTake care to ensure that tree trunks are straight when you position them in the hole. If you are planting
a budded tree, face the bud toward the afternoon sun. This will shade the inside curve above the bud, which may be sensitive to excessive sunlight and heat. White paint on this area can be helpful for sensitive species.Another factor to consider when positioning trees or Figure 2. Anchor staking prevents the root ball from pivoting before the transplant establishes roots outside the root ball. Two or three stakes in firm ground and tied low to the trunk are adequate. Use wire and soft wrap material, and remove after the first year.Figure 3. Support staking is necessary when a tree’s trunk is too thin to support the tree unaided. Use one or two stakes several inches away from the trunk and run a soft wrap material from near the top of the stakes to the trunk. Ensure that the trunk has some room to flex and move. Tie the stakes to the trunk about 6 inches above the lowest point where you can grasp the trunk and the crown still will right itself after you deflect it.
shrubs is crown symmetry. Orienting the less-developed
side of the crown toward the sunniest exposure will encourage it to grow more quickly and balance out the crown over time.Once you dig the holes and position and prepare the tree or shrub root balls, backfill the planting holes with the existing unamended soil. Do not incorporate organic matter or sand into backfill soil for individual planting holes because doing so will create differences in soil-pore sizes. Pore-size differences cause problems with water movement and root growth between the root ball, the backfill and the surrounding soil.Do not backfill the entire planting hole in one operation.
Backfill half the soil, then water thoroughly to settle out air pockets and re-moisten the soil in the root ball. Finish backfilling and water again.You can add fertilizer as you backfill, provided you use a slow-release form (resin- or sulfur-coated, briquette
or compressed) at a low rate (1 pound of actual nitrogen per 1,000 square feet of planting-hole surface area). Avoid using fast-release agronomic fertilizers (such as ammonium nitrate) because these can dehydrate
tree and shrub roots if you apply too much.Once you complete backfilling and watering, decide if you want to apply a surface treatment for weed control. Your primary options include mulch, landscape fabric or pre-emergence herbicides—alone or in combinations.• Mulch. Availability, appearance, weed-suppression capabilities and cost determine what type of mulch product to use—organic or inorganic. Most landscapers
prefer organic mulches for appearance, moisture conservation and organic-matter replenishment of the soil. However, inorganic mulches better resist decomposition. Apply no more than 2 to 4 inches of mulch. Use more of materials with large particle size to form a light barrier that inhibits weed-seed germination. Keep mulches from touching tree and shrub stems to reduce moisture damage and rodent feeding (when using organic mulches) and bark abrasion (when using inorganic mulches).• Physical barriers. If you use a physical barrier with your mulch, do not use solid plastic. It blocks important moisture and gas exchange between the soil and atmosphere. Instead, use one of the porous woven or non-woven synthetic geotextiles or landscape
fabrics.• Pre-emergence herbicides. Select your herbicide based on the major species of weeds you have to control.
The label should list the herbicide as safe for the tree and shrub species around which you’ll apply the material. Also, be sure that your rate and timing are correct for maximum effectiveness. If you use a mulch in addition to a pre-emergence herbicide, apply the mulch first, then the herbicide.Figure 4. Guying is an alternative to support staking. You still must tie the tree loosely, with room to move, at about the same point up the trunk. Use non-abrasive tie material.PALM SUPPORT BRACINGBurlapNails support brace to 2 x 4 vertical. Do not drive nails into trunk.Strap 2 x 4 verticals to trunk2 x 4 verticals2 x 4 support bracesPALM TRUNKFigure 5. Bracing with 2 x 4s is a good method of stabilizing palms until they become established. Instead of 2 x 4s, some installers use cables anchored to the ground. Protect the palm by wrapping burlap underneath the 2 x 4 verticals. Also, never drive nails into the trunk.
STAKING AND OTHER SUPPORTSShrubs seldom require staking. Trees, however, often require added support until their trunks grow and strengthen. Further, you may need to supply physical protection for a transplant vulnerable to vandalism, mower damage or some other hazard. Here are some of the common methods of supporting and protecting trees:• Anchor staking. Staking to anchor the root ball is helpful in windy locations or areas where the tree will be prone to disturbance. Roots growing from the root ball into the surrounding soil may break if you allow too much movement. Therefore, many arborists use anchor stakes to prevent such movement. These consist of short stakes, usually two or three, in firm ground just outside the root ball. These are attached low on the trunk with wire and soft wrap material to protect the trunk (see Figure 2, page 30). One year is usually adequate time for anchor staking.• Support staking. Staking for trunk and crown support
is not necessary for most shrubs and many trees. You should leave those that clearly are self-supporting unstaked. However, many trees, especially container-grown specimens, have spindly trunks, and you must stake them until they develop sufficient trunk size. Tying trees rigidly to one stake is not a proper way to stake trees, even though many container plants come from the nursery in this state. Trees treated this way are not able to develop thickened trunks with any speed and often develop wounds from friction with the stake.A better method is to use one or two stakes several inches away from the trunk. From near the top of the stakes, you can run wire to the trunk in a figure-eight arrangement (see Figure 3, page 30). To determine where to tie to the trunk, grasp the trunk, deflect the crown slightly and see if it rights itself. Tie to the trunk about 6 inches above the lowest grasping point that allows the crown to return to an upright stance. You must use a soft material to protect the trunk from damage from the wire. Landscapers often use cut sections
of rubber garden hose, but even this can cause trunk injury. Suppliers carry cloth, polyethylene or other tie material manufactured for this purpose, and these provide adequate support with minimal risk of trunk injury. Wood is the most common stake material, but metal stakes are adequate, though not always as attractive.Staking may be necessary for 1 or more years, depending
on the growth rate of the tree and the taper of the trunk. Therefore, you must use your judgment when deciding when to remove the stakes. As soon as the tree is self-supporting, remove the staking. However,
you may wish to leave the stakes in place for physical protection of the trunk.• Guying. This involves running cord or cable from stakes near ground level to a point (see subheading, “Support staking,” above Figure 4 at left, to determine tie location) higher up on the trunk (see Figure 4, at 31). Arborists use guying more often with large transplants, but it may succeed for smaller transplants as well. Though guying is an acceptable alternative to staking, it requires the same precautions. For example, use material that won’t wound the trunk, and tie the guy lines loosely enough to allow the tree some room to flex and move with the wind. • Protective staking. Depending on the site, you may wish to install stakes to provide trunk protection for a newly planted tree. These usually consist of nothing
more than two or three stakes 1 to 2 feet from the trunk. They should be tall enough to provide protection from whatever hazard is likely to be present—
mowers, for example.Landscape professionals have devised many other ingenious support-staking schemes. The important factors are: Tie to the trunk at the proper height.Figure 6. To avoid overwatering new transplants, construct a small basin within a larger one around the planting
hole. The berm of the smaller basin should be just above the perimeter of the root ball. Fill the inner basin with water daily and the outer basin every 2 to 3 weeks.
TLD Allow enough flexibility and movement to encourage
the trunk to thicken and become self-supporting.
Do not use materials that could wound the tree’s trunk. Remove staking or guying as soon as the tree is self-supporting.Other structures, such as for protection, may be appropriate
in certain situations. These could include extensive
protective structures for preventing vandalism or animal damage, or metal grating over the root-ball area to prevent traffic damage to a young root system. Large palm trees require bracing with boards to keep their trunks upright until roots become established (see Figure 5, page 31).WATERINGNeedless to say, desiccation is the greatest threat to newly planted trees and shrubs. Therefore, irrigation is the most critical need of transplants until they establish
root systems well beyond their original root ball. Newly planted trees and shrubs vary in their water requirements. Bare-root plants should not need irrigation (aside from watering at planting time) until at least 2 weeks after growth commences. At the other end of the scale, plants in full leaf may need daily irrigation
during warm weather.The goal of watering a new transplant is to keep the root ball and the surrounding backfill adequately moist. However, the danger of overwatering and creating
a “bathtub” in the planting hole, especially in tight soils, is a real one. Some plants—for example, palm trees—are extremely sensitive to overwatering. At planting, many landscapers build a berm around the perimeter of the planting hole to create a water basin. To minimize the risk of overwatering, construct a smaller berm within the larger one—just outside the root ball and high enough to hold enough water to re-wet the root ball (see Figure 6, page 32). Filling this smaller basin daily with water will keep the root ball and a bit of the surrounding backfill moist. Irrigate the larger basin every 2 or 3 weeks. After the first few days of irrigating the inner basin, lengthen the watering interval until the first signs of wilting appear. Then adjust the watering interval so that it is one day shorter than the length of time in which wilting occurs. Continue on this schedule for a few weeks. Then readjust the watering frequency again, using the same method. You can gradually cut back watering frequency in this way.You can apply water in various ways. Hand watering is most common for new transplants, but drip works well too. Other systems, such as water-filled plastic bags you lay around the trunk, also perform well. The important point is that no irrigation system eliminates the need to keep track of the amount of water you apply. You must keep the root ball and surrounding backfill wetted but not constantly saturated.A FEW FINAL PLANTING NOTES• Pruning. Do not prune off one-quarter to one-third of the stem and leaf growth as was once recommended. Newly transplanted trees and shrubs need the growth regulating hormone auxin, which is made by the terminal
buds, and the sugar made by the leaves for root growth. Limit structural pruning to removing problems—multiple leaders, narrow crotch (branch-attachment) angles, water sprouts, basal suckers, and dead or infested branches. See Chapter 11 for more information on training young trees.An exception to this rule is palm trees. Many species of large transplanted palms ideally should have all of their fronds removed to reduce water loss during establishment.
Aesthetic considerations discourage this, however. At a minimum, though, remove the lower one-half of the fronds. Tie the remaining fronds up with degradable twine. This protects the apical bud during transplanting and reduces water loss until the twine degrades after a few months and releases the fronds.Based on the tree’s environment, decide whether to apply a wrap or guard to its trunk. Consider these options for specific tree-planting sites:• Wraps. They can be beneficial in heat sinks, such as tree islands in parking lots. A white wrap, which reflects heat, is beneficial if you transplant your tree during the spring or summer. Be sure the wrap doesn’t stay on the tree trunk for more than a year. Don’t attach
the wrap with wire, electrical tape, plastic ties, nylon rope or other materials that have no give and resist decomposition.• Guards. If tree trunks need physical protection from equipment, animals or people, use a guard that doesn’t touch the trunk and permits air circulation. Guards serve a function similar to protective staking but may not prevent equipment from bumping the tree, depending on the product. Coiled plastic guards that unfurl to fit the tree’s trunk are inexpensive and effective protection from trimmer damage—an all-too-common cause of injury for young trees. If the guard will be in place for multiple years, be sure to periodically inspect it and loosen it if necessary to keep it from damaging an ever-widening trunk.It is important to remove all tags and labels from trees and shrubs to prevent girdling of branches and trunks.
Annuals, Perennials and Bulbs
Landscapes often include beds dedicated to pro-viding color. Such plantings generally consist of herbaceous plants that provide abundant bloom, colorful foliage and reliable growth. Well-executed color beds usually are the most noticed and visually appealing aspect of a landscape. Many of these, especially those that incorporate annuals and certain bulbs, tend to be high-maintenance affairs, so you’ll employ them to the degree that your client or facility is willing to pay for them. Herbaceous plantings consist of ornamental plants that we group into three categories: annuals, perennials and bulbs. A fourth group, biennials, includes plants that live for 2 years. For practical
purposes, these may be treated as long-lived annuals. We’ll discuss the selection and maintenance of each type in more detail below.A FEW NOTES ON DESIGNCreative landscapers have devised an almost infinite variety of herbaceous-planting designs. Because of the vast number of plant varieties and flower colors available,
the range of possibilities is nearly limitless. Some designers tend toward formality and create symmetrical, well-structured displays. Others prefer informal, natural-looking plantings. There is no absolute right or wrong Apr.30May 30May 30May 30Feb.28Mar.30Apr.305-305-305-304-30May 304-304-304-30Feb.28May30Jan.30Jan.30Feb.284-303-302-28Jan.30Feb.28Mar.304-305-205-30May 304-304-203-206-304-305-30May30Apr.306-306-305-306-30May 30May 10May 20May 10May 20May 30May 10May 10May 10Apr. 305-304-30May 30Apr. 30Apr. 30Apr. 10Mar. 30Apr. 20Mar. 30Mar. 30Mar. 20Mar. 20Mar. 10Feb. 28Feb. 18Feb. 18Feb. 8Jan. 30Feb. 8Jan. 30Feb. 18Jan.3Jan.20Feb. 8Feb. 18Feb. 18Mar.30Apr.20Mar.30Mar.20Mar.204-10Apr.20Apr.30Apr.10Apr.304-204-304-205-104-305-105-105-306-10May 20May30May 20May 10Apr.305-104-304-20Apr.204-205-104-104-203-30Mar.103-20Feb.18Jan. 30Feb.28Mar.10Mar. 10Mar. 20Mar. 30Apr. 10Apr. 20Apr. 30Apr. 20Apr. 30May 10May 20May 30June 10May 10May 20May 30Apr.304-105-104-205-104-305-305-204-305-104-305-305-105-20AVERAGE DATES OF LAST KILLING FROST IN SPRINGThis map indicates the average date of the last spring frost for regions of the United States. To use this as a guide for planting in your region, you should add some time—a couple of weeks, at least—to these dates before planting tender bedding. Because the dates are averages, a frost is likely to occur after these dates in as many years as not.Source: U.S. Department of Agriculture.Frost free.Killing frost liable annually.Killing frost liable in one-half the years.
in most cases, though some authorities have strong (and often widely differing) preferences.
However, certain obvious guidelines are useful to follow. For example, if you mix different-sized varieties of bedding, make sure larger types will not hide smaller plants from view. Avoid overly complex designs—they tend to get lost, visually speaking. Also, be consistent with the character, formality and scale of existing landscape features. Some color combinations are definitely more pleasing than others, but do not be afraid to try new combinations. Some of the most dramatic plantings occur when designers
use unconventional color mixes that would be considered “wrong” by some rules. Do not forget that bedding plants have one primary purpose: to look good. Following design guidelines should be a means to that end, not an end in itself. If guidelines hinder creativity, they are no longer useful. Also remember that, as in all matters of opinion, no particular look will please everyone. Make note of attractive displays you see, and take pictures if you have the opportunity. These are sure to spur new design ideas.When you plan bedding displays, make scaled drawings
based on bed measurements. After you decide on the kinds of bedding you’ll use, you can calculate plant-material needs based on plant spacing. Spacing is an important matter (see “Spacing and plant-material calculations,” above right). Spacing plants too widely leaves the canopy open for too long, which may be unattractive and can increase weed problems. Therefore, do not try to save money by planting sparsely. Spacing plants too closely will force them to compete with each other and can increase disease problems. Further,
it wastes money by utilizing more plant material than necessary. Proper spacing depends on the growth rate and habit of the plant variety and the ultimate size the plants will attain but ranges from about 6 inches to 1 or 2 feet for large bedding plants. Spacing should approximately
reflect mature plant size. Bulb spacing falls within a similar range but do not space them wider than 10 to 12 inches because they will not fill in as do other bedding plants. When you install bedding plants, stagger the rows. This will not affect the number of plants you need but speeds up canopy closure somewhat.You can rotate beds once, twice or more times annually, depending on the resources available. You can plant cool-season annuals in spring, follow them with summer annuals, after which you can install bulbs. Some professionals
use plants such as chrysanthemums or kale for a brief splash of additional color after they remove summer annuals but before they install bulbs in the fall.Another strategy gaining in popularity is intermixing cool-season annuals such as pansies with bulb plantings. This provides additional color as well as ground cover and helps distract the viewer from unattractive post-bloom bulb foliage.PLANT TYPES# Annuals, strictly speaking, are plants that grow, flower and die within the same season. However, this category is somewhat arbitrary because many “annuals” actually are tender perennials that simply are discarded at the end of the growing season. Annuals are further divided into cool-season and summer types.Annuals are available in almost any color, texture or size you could want. Growers often supply “lines” or “series” of a species and variety that include plants that are similar in most respects but have different flower colors. These can be useful in color designs.• Cool-season annuals tolerate frost and typically do not thrive in summer heat (though exceptions exist). Landscapers
in colder climates plant them in spring for early color and, to a lesser extent, in fall for color until cold weather ends the growing season. If this conflicts with your bulb-planting operations, however, you may wish to omit fall color where you’ll be installing bulbs. This partly is a matter of budget, because fall bedding may supply color for only a short time. In warm-winter areas, cool-season annuals are planted in late summer and fall for winter and spring bloom. In high elevations and other very cool climates, you can treat cool-season annuals as summer annuals.• Summer annuals mostly do not tolerate frost. Therefore, CSPACING AND PLANT-MATERIAL CALCULATIONSConsider a 10- by 10-square-foot bed that you want to fill with ageratum spaced 8 inches apart (ageratum’s approximate mature size). Eight-inch spacing means each plant will take up an area 8 inches by 8 inches, or 64 square inches. The bed is 100 square feet but you need to convert to square inches. To do this multiply by 144 (the number of square inches in a square foot), which gives you 14,400 square inches. Divide this by 64 (square inches needed per plant), and you find you’ll need 225 plants to fill the bed. Actual plantings are usually a bit more complex and may require you to estimate areas for oddly shaped beds, but the calculations are essentially the same.Always add a “fudge factor” to the plant material totals you calculate. An extra 5 or 10 percent will make up for weak or damaged plants, empty pack cells or last-minute design adjustments that require a few landscapers install them after the danger of frost has passed. Installation times vary according to region (see “Average dates of last killing frost in spring,” page 34). Summer annuals provide color for the duration of the warm season and are discarded when it’s time for the next changeout, often in September or October.# Bulbs, being long-lived, actually fit the definition of perennials. However, because they possess various qualities that set them apart from other perennial plants, it is convenient to group them separately. This group encompasses a large number of plants. Most traditional bulbs belong to the lily family (for example, tulips), the onion family (for example, daffodils) or the iris family. However, the term bulb is broadly applied to include members
of various other families that produce underground structures such as tubers or rhizomes that, technically, are not bulbs. These include begonias, caladiums, cannas, dahlias, poppies and even some orchids, among others.Many bulbs are quite hardy and should be planted in the fall for spring displays or even left in the soil permaAVERAGE
ANNUAL MINIMUM TEMPERATURE (BY ZONE)This map illustrates plant-hardiness zones as determined by the U. S. Department of Agriculture. These zones are based on average annual low temperatures, as listed on the map. Hardiness ratings given to plants indicate the zone in which a plant should be reliably hardy. Most plants can survive relatively mild years in regions one or two hardiness zones colder than their rating but will perish in a normal or harsh winter there. In addition, healthy, well-established perennials given good care—such as thick cover in winter—often can tolerate conditions somewhat colder than their rating would indicate. Conversely, poorly established, unhealthy plants often perish in temperatures they would tolerate if healthy. Extraordinarily cold winters can kill plants growing well within their usual zones of tolerance.Source: U.S. Department of Agriculture.
nently for naturalizing. Others are restricted to seasonal plantings and must be lifted and stored or discarded at the end of the growing season. Hardiness ratings for bulbs indicate only where they will tolerate winter cold. This does not mean you cannot grow them in colder climates during the warm season.Whether you can reuse bulbs depends
on the type of bulb as well as the care you’ve given them. For example, many kinds of tulips lose vigor and do not provide consistent bloom after the first planting. These often are discarded or given away. In any case, do not use them again for a formal planting where a non-uniform
bloom would be noticeable—the money you’ll save by reusing them is not worth poor results.Other bulbs, daffodils being a good example, perform satisfactorily for many years and naturalize well. Thus, you may wish to replant them in a location where you can leave them permanently or save them for future plantings. All bulbs benefit from good care and will come back stronger as a result. Still, if you intend to reuse bulbs, select types that are suitable for this purpose. If you are establishing a permanent bulb planting, use naturalizing
types that will provide good long-term performance.# Perennials are long-lived herbaceous
plants that regrow each year from underground parts. Some perennials
live indefinitely, while others
decline or die after several years. Compared to annuals, perennials are relatively low-maintenance, but they are not totally free of upkeep. For example, most periodically require division of their underground parts when dormant to maintain vigor. Still, perennials may be considered practical
low-maintenance alternatives to annuals in spots where you want some color. They are not as reliant on continuous
water and nutrients, and they avoid the labor-intensive changeouts that bulbs and annuals require.Perennials tend to bloom for only a limited time—typically a few weeks to a month or so. Designers compensate
for this by creating mixed perennial plantings that include species with a wide variety of bloom times. A well-designed perennial planting of this sort can provide season-long color. Because they increase in size every year, perennials eventually can provide impressive blooms.The chart above and those on pages 38, 39 and 40 list BULBSScientific nameCommon namePlanting (inches)Hardiness (USDA Zone)Spring-flowering typesAllium giganteumGiant onion105Convallaria majalisLily of the valley14Crosus spp.Crocus44Cyclamen neapolitanumCyclamen*0.55Fritillaria imperialisFritillary55Galantus nivalisSnow drops56Hyacinthus orientalisHyacinth66Iris spp.IrisCaries5 (most types)Muscari armeniacumGrape hyachinth35Narcissus spp.Daffodil, jonquil63Scilla spp.Squill5 (most types)Triteleia spp. Triteleia4 to 66Tulipa spp.Tulip5 to 63*Fall BloomerSumer-flowering typesAgapanthus spp.Africian Lily29Amaryllis belladonnaBelladonna85Anemne coronariPoppy anemone28Begonia x tuberhybridaTuberous begoniaSurfaceTenderBletilla striataHardy orchid46Caladium x hortulanumCaladium28Canna x hybridaCanna39Clivia miniataKaffir lily210Colocasia antiquorumElephant earSurface8Crocosmia x crocos miifloraMonbretia37Crocus sativusSaffron34Dahlia x cultorumDahlia4 to 6TenderFreesia x hybridaFreesia29Gladiolus callianthusAcidanthera410Gladiolus hybridsGladiolus4TenderHippeastrum hybridsAmaryllisSurface10Ixia spp.African corn lily47Lilium hybridsLily6 to 83 (most types)Pancratium maritimumSpider lily67Polyanthes tuberosaTuber rose18Ranunculus asiatucuspersian buttercup26Sparaxis tricolorWand flower29Tigridia pavonia Tiger flower46Tulbaghia violaceaSociety garlic29Watsonia pyramidataWatsonia4TenderZantedeschia spp.Calla lily49Zephyranthes spp.Zephyr lily27
bulbs, annuals and perennials commonly
used in landscape plantings. These lists are by no means complete. However, the plants included account for most herbaceous plantings you see. Most of these genera and species have been well-developed by breeders so that a wide variety of flower colors, sizes and environmental adaptations are available. Remember that many other, less well-known types are available through specialty dealers. Also recognize that significant differences
exist between varieties—differences
that matter in a design. Acquaint
yourself with specific cultivars before using them in plantings.SPECIESWhile reviewing the species in the tables, remember that these lists are not complete. They do, however, include the most widely used, well-developed lines of bedding plants available to the industry. Many lesser-
known species are available from some suppliers and can perform quite well. Thus, omission from these lists is not meant to imply criticism. Also be aware of the following points as you use these lists:• Hardiness-zone ratings correspond to those shown by the map on the opposite
page. Hardiness varies among cultivars of a species and among species within a genus. Further, environmental and physiological factors affect hardiness as well. Thus, consider the ratings given to be approximate.
• Bloom times also are approximate. Yearly weather variations, site and exposure factors, climatic region and cultivar characteristics cause bloom times to vary.• Sizes of annuals have been listed in general terms because
most commercial bedding-plant species are available
in cultivars with a wide range of height and spread. Likewise, flower colors are not included because, again, breeders have created a large number of color options for most of the plants listed.• Exposures indicated in the tables are those that allow the plants to perform at their most optimum. However, cultivars of some species are available that thrive in exposures different than those listed. Further, many of these plants acceptably tolerate exposures outside their optimum parameters, even though they may not perform at their best.• Categories are, in some cases, somewhat arbitrary. For example, many suppliers consider several species, which are listed as bulbs, to be perennials, and vice versa. For ANNUAL BEDDING PLANTSSpeciesCommon nameExposureHeightSummer annualsAgeratum houstonianumAgeratumSun LowAlcea roseaHollyhockSunTallAntirrhinum majus**SnapdragonSunLow to tallBegonia sempelflorensBegonia (fibrous)Shade, part sunLowCapsicum annuumPeppersSunLowCatharanthus roseusVincaSunLow to mediumCelosia cristataCockcombSunLow to mediumCentauria cyanus**CornflowerSun Low to mediumCleome spinosaCleomeSunTallColeus hybridsColeusShade, part sunLow to MediumCosmos spp.CosmosSunMedium to tallDahlia spp.DahliaSunMedium to tallDianthus spp.PinksSun, part shadeLow to mediumDyssodia tenuilobatuDahlberg daisySunLowFelicia amelloides*Blue margueriteSunMediumNicotiana alataFlowering tobaccoSun. part shadeMedium to tallGazania ringensGazaniaSunLowGomphrena globosaGomphrenaSunLow to mediumImpatiens hybridsNew Guinea impatiensPart shade, sunLow to MediumImpatiens walleranaImpatiensShade, part sunLowIpomoea spp.Morning glorySunViningKochia scopariaKochiaSunLow to mediumLantana spp.u*LantanaSunLow to mediumLobelia erinusuLobeliaPart shade, sunLowLobularia maritimeu**Sweet alyssumSun. Part shadeLowMelampoduim paludosumMelampodiumSunLow to mediumNierembergia spp.Cup flowerSunLowPelargonium hybridsGeranium SunMediumPelargonium peltatumu*Ivy-leaf geraniumSunLow to mediumPentas lanceolata*PentassunMediumPetunia hybridsPetuniaSunLowPortulaca grandiflorau Moss roseSunLowRudbeckia hirtablack-eyed SusanSunMedium to tallSalvia farinaceaBlue salbiaSunMedium to tallSalvia splendensRed salviaSunMedium to tallSanvitalia procumbensuCreeping zinniaSunLow to mediumSenecio spp. Dusty millerSunLow to mediumTagetes spp.MarigoldSunLow to mediumTithonia rotundifoliaMexican flowerSunTallTorenia founieriWishbone flowerShade, part sunLow to mediumTrapaeolum majusNasturtiumSunMediumVerbena hybridsuVerbenaSunLowZinnia elegansZinnaSunLow to tall*Used as annual bedding in some regions—better know as a perennia in others. **Frost tolerant. Also can be used as cool-season bedding. uPopular in baskets due to trailing growth habit.
practical purposes, this matter is of little concern. Whatever
the underground structures may be, if the plant is hardy, you can leave it in the ground. If not, you must dig it up and store it during the dormant season. Further, certain species listed as annuals are actually perennial, even though we typically treat them as annuals and discard
them after one season.• “Cool-season” and “summer” designations are climate- and region-dependent. Some cool-season species may be used only in spring and fall in hot-weather regions but all year in cool climes. Other species may tolerate frost but also thrive in heat. These are footnoted in the tables. • Perennials listed are all hardy to at least Zone 5, but many are hardier than this and will perform quite nicely in other zones.• Finally, remember that plants have just one botanical name, but often have several common names. Thus, the common names you see, while widely recognized, are not necessarily the only ones used for these species. There is no easy way to deal with this problem, so whenever possible, it is better to use botanical names to avoid confusion with other species that may share a similar common name.SITE AND SOIL PREPARATIONLike all plants, bedding plants have specific environmental
needs. Some prefer shade, others need full sun. Be sure you’re putting the right plant in the right place and using species appropriate for the season.Proper soil preparation is, of course, important for all plants. However, it is especially critical if you expect to succeed with annuals. Annuals have only one season in which to provide blooms and must have good growing conditions from the start to perform to their potential. Even though most bulbs are virtually guaranteed to bloom, they, too, will yield better results if you treat their soil similarly.Beds that receive regular rotations may need little preparation—the soil should be quite loose and, if prior care has been adequate, fertile and rich in organic matter. However, newly created beds or poor soil conditions may necessitate
substantial inputs of labor and materials to bring the soil up to a quality that will allow annuals to thrive.Till soil to a depth of at least 1 foot. Good drainage is important but so is water retention—
annuals will languish if conditions are either too wet or too dry. Add generous amounts of organic matter to improve soil structure and water retention. Beds that have been worked and amended frequently may need less organic matter. Peat, finely ground bark and compost from various sources are commonly used soil amendments for seasonal beds.Perennials enjoy similar soil conditions, but you should till the soil a bit deeper—to 18 inches if possible. Because perennials are relatively permanent, ensure you perform all necessary soil modifications before planting, when you can incorporate amendments more easily. While you are tilling the soil and adding organic amendments, also add fertilizer. Many analyses and brands of fertilizer are adequate for this purpose. A key point to remember is that you should avoid excess nitrogen. This promotes vigorous vegetative growth but often at the expense of flowering. Also, you should use a fertilizer with ample phosphorus and potassium. Fertilizers such as 5-10-10 and 5-10-15 are commonly used and quite satisfactory, though many professionals use balanced fertilizers—10-10-10 or 20-20-20—with good results. Apply the fertilizer at the package-recommended
rate and incorporate it into the soil along with the other amendments you are adding.TRANSPLANTING# Annuals. Landscape professionals rarely plant bedding from seed. It is far easier and usually yields better success to purchase young plant material from a reputable supplier.
Select bedding plants that are pest- and disease-free, stocky, actively growing and have not been allowed to outgrow their containers. Bedding that has been held too long and has “stalled” will not perform well. Suppliers typically start to stock bedding around the time that frost is no longer a danger, and this is the time for planting. Don’t be tempted to plant too early when you see some nurseries stocking bedding plants while a danger of frost still exists.Bedding plants typically are sold in flats, which hold cell packs of various dimensions and counts. Flats with higher plant counts also have smaller plants. Smaller plants can be purchased for less money per plant, but ANNUAL BEDDING PLANTSSpeciesCommon nameExposureHeightCool-season annualsBrassica oleraceaKaleSunLow to mediumCalendula officinalisCalendulaSunMediumChrysanthemum spp.*ChrysanthemumSunLow to mediumGerbera jamesonii*Transvaal daisySunLow to mediumLathyrus odoratusSweet peeSunViningMatthiola incanaStockSunMediumPapaver spp.*Poppu (Iceland, others)SunLow to mediumPrimula spp.*PrimroseSun, Part shadeLowSalpiglossis sinuatePainted tongueSunMediumViola spp.PansySun, part shadeLow*Used as annual bedding in some regions—better know as a perennia in others. **Frost tolerant. Also can be used as cool-season bedding. uPopular in baskets due to trailing growth habit.
larger plants provide color a bit sooner, so there’s a tradeoff between the two. The time gained with larger plants is not great, so the most important
factor is that the plants be of high quality, regardless of size.Annuals in plastic cell packs are easily removed. Gently squeeze the cell to loosen roots and the plant should easily slide out. Plants with sturdy stems may be pulled out by the stem. However, if there is any danger of injuring the plant, turn the pack over and let the plant fall out.To make it easier to implement your design, use some method of laying out the planting before
actually placing the bedding in the ground. This allows you to make any needed fine-tuning to the design without having to dig up plants.Some installers use wooden frames with string grids as planting guides. Others use augers to dig properly placed, well-defined holes in advance of the planting crew. Or, you can remove bedding plants from their packs and arrange parts of the design before actually planting the material in the soil. However, you should limit this practice according to weather conditions. Sunny weather can desiccate roots quickly, so this may not be appropriate on some days. Whatever method you use, it is better to plant bedding right the first time, for obvious reasons.Transplanting is simple. Just dig a hole deep enough that the top of the plant’s roots are level with the surrounding grade. Soil mounded up around the stem is a practice you should avoid because it often promotes stem diseases. You can use a trowel, but well-tilled soil may be loose enough for you simply to use your hands. Small, powered augers sized for bulbs and bedding
plants are available for planting holes.Many installers place bone meal or superphosphate
in the planting hole to supply additional
phosphorus for quick establishment. Plants probably gain little benefit from this practice if the soil already is fertile and well-prepared. It causes no harm though, and many planters feel it is a good practice “just in case” soil fertility is deficient.To the extent possible, avoid compacting the soil as you work in and around the bed. Work from the center of the bed outward to avoid disturbing the bedding you’ve already planted. When you have finished planting, immediately water the bedding thoroughly. Some landscapers apply mulch at this point. While it is true that this may conserve some water, the bedding will HARDY PERNNIALSSpeciesCommon nameBloom time*ExposureAchillea millefoliumYarrow6-9SunAcanthus mollisBear’s breech5-6SunAjuga reptansCarpet bugle4-6Part shadeAquilegia spp.Columbine5-6Sun, part shadeArtemisia schmidtiana‘Silvermoud’NASunAsclepias tuberosaButterfly milkweed6-7SunAster spp.Aster6-9SunAstilbe hybridsFalse goatsbeard6-8Part shadeClematis spp., hybridsClematis5-8SunCoreopsis spp.Coreopsis6-9SunDelphinium spp.Larkspur5-6Part shadeDianthus spp. Pinks5-8Sun, part sunDicentra spp. Bleeding heart5-8Shade, part sunDictamnus albusgas plant5-6SunDigitalis spp.**Foxglove5-9Shade, part sunEchinacea purpureapurple coneflower7-9SunErysimum supp. WallflowerVariesSunGaillardia x grandifloraBlanket flower6-9SunGalium odorataSweet woodruff5-6Shade, part sunGaura lindheimeriGaura7-9SunGeranium spp.Cranesbill5-7Sun, part shadeGypsophila paniculataBaby’s breath5-8SunHemerocallis spp. Gaylily7-9SunHeuchera sanguineaCoral bells5-6Sun, part shadeHibuscus hybridsRose mallow7-9SunHosta spp.Plantian liliy7-9Shade, part sunIberis sempevirensCandytuft4-9SunLamium maculatumDeasnettle6-9ShadeLavandula spp.Lavender6-9SunLiatris spp.Blazing star7-9SunLimonium latifoliumStatice6-9SunLinum perenneFlax5-7SunLiriope muscariTurf lily8-9Sun, part shadeLobelia sppl Lobelia7-9Sun, part shadeLupinus spp.Lupine6Sun, part shadeLythrum scalicariaPurple loosestrife6-9Sun to shadeMiscanthus sinensisEulaia (grass)NASun, part shadeMonarada didymaBee balm6-8 SunNepeta mussiniiCatnip5-8SunOenothera spp.Evening primrose5-7SunPapaver orientaleOriental poppy5-6Sun, part shadePaenoia hybrids Peony5-6SunPenstemon spp.Beard tongue5-6Sun, part shadePhysostegia virginianaObedient plant7-8Sun, part shadePhlox paniculataSummer phlox6-9Sun, part shadePhlox subulata Creeping phlox3-5Sun. part shadePlatycodon grandiflorum balloon flower6-9Sun, part shadePolemonium caeruleumJacob’s ladder5-6Part shadePrimula spp.Primrose4-6Shade, part sunRudbeckia spp.Cone flower7-9SunSalvia spp.Sage6-8SunScabiosa caucasucaPincushion flower6-10SunSedum spp.Sage6-8SunThalictrum spp.Rue6-8Sun, part shadeTrollius x cultorumGlobeflower5-7Sun, part shadeVeronica spp.Speedwell5-7Sun, part shade*Number indicates months. January=1, February=2, etc. ** Some species and varieties are biennial.
soon form a canopy that not only conceals the mulch but also performs the same function as the mulch. Therefore, the value of this is largely aesthetic. However, that is enough justification for many operations. Plus, the mulch provides additional organic matter when it is tilled in during the next changeout.After you’ve installed bedding, the main problem becomes
one of keeping the plants adequately irrigated until they are well-established. This may be easy or difficult, depending on weather conditions. But count on having to supply water as needed, perhaps daily, until the plants are established. The plants should become rooted well enough in the surrounding soil after a week or two for you to lessen the frequency of irrigation, though this will depend on your climate and weather conditions.# Bulbs. Plant spring-flowering bulbs in the fall anytime before the ground freezes. Although exact timing is not critical, an earlier planting is beneficial. This allows bulbs to establish roots during the relative warmth of fall. You probably will plant bulbs in the same beds you use for summer annuals. Thus, in practice, you won’t be able to install bulbs until you’ve removed the summer
bedding—September or October in most parts of the United States. In warm-winter regions, you can also install intermixed cool-season bedding at the same time if you wish to use such a design.In regions with warm winters, you should refrigerate spring-blooming bulbs for about 4 weeks before you plant them in the fall. This helps prevent them from blooming prematurely.Bulb designs are easiest to implement if you lay out the design on the soil surface beforehand. However, you cannot
always tell the difference between bulbs of different varieties, so take whatever precautions are necessary to avoid mix ups. After all, you may not know if you’ve made such a mistake until the bulbs bloom, and then it is too late.Because bulbs will not form a solid canopy, the planting
pattern is much more apparent. Therefore, formal plantings require consistent spacing and straight lines for best appearance. Surveyor’s string or some other device can help you keep planting lines straight and spacing regular.Of course, informal or “natural” plantings do not require
such attention. These should relate more to other aspects of the landscape such as contours, rocks and other plants, and should be spaced with a more random appearance.Plant bulbs with the roots down. Usually, this means pointy side up, but it’s not always obvious with some bulb types, so make sure you know which side is up before you plant. Planting depth varies according to species (refer to the planting depths given in the table on page 37). Ensure you plant bulbs at the proper depth, especially in areas subject to frost heave. Loose soil may be soft enough for you to use your hands to dig planting holes. Otherwise, use a trowel or an auger. Remember to water in bulbs after planting, as you would other bedding plants.# Perennials require planting treatment more similar to shrubs than annuals (see Chapter 5). Loosen soil around the planting site to a depth of 12 to 18 inches. If you wish to add fertilizer at planting, use a balanced product at one-half the label rate and mix it thoroughly into the backfill. As with any newly planted ornamental, be ready to supply frequent irrigation, if necessary, until the plant is solidly established. Surface mulching is beneficial for weed suppression and water conservation around perennials.
Unlike annuals, perennial plantings usually will not form a closed canopy, nor will you work the soil in these beds regularly. Therefore, weed control may require greater long-term efforts in perennial plantings.AFTERCAREFERTILIZATIONFertilization of annual plantings is generally a simple matter. After transplanting, apply a label-rate dose of fertilizer every several weeks. Use a product with a nutrient ratio similar to that which you used at planting. Often, bedding plants have achieved a closed canopy by this point. In this case, many grounds-care professionals prefer using a liquid-applied fertilizer, but granular products also are effective if you water them in properly. Further, granular fertilizations may last longer, providing nutrients for up to 6 to 8 weeks, compared to as little as 2 to 3 weeks with foliar feeding. Take care to avoid foliar burn if you use a liquid fertilizer, especially in hot, sunny climates.Fertilize spring-blooming bulbs when the foliage is actively growing. Specialty “bulb food” fertilizers have DISEASE-PREVENTION CULTURAL PRACTICES• Provide pathogen-free growing medium or soil.• Buy only pathogen-free plants or bulbs• Maintain good drainage• Encourage dry plant surfaces by providing good air circulation and sunny exposure.• Keep plants vigorous and healthy with appropriate cultural practices.• Practice good sanitation—remove old and dead plant parts from plantings.
appropriate nutrient ratios—the key is high phosphorus (relative to the other nutrients).Perennials are less reliant on fertilization than annuals. Their more well-established root systems should be able to provide the plant with adequate nutrients assuming the soil is reasonably fertile. However, like shrubs, perennials may benefit from at least one fertilization in spring, using a balanced fertilizer. Some growers also recommend an additional fertilization, but this is not critical. Granular and foliar-applied liquids are both effective. DEADHEADINGThe practice of removing old flowers and young fruit, or deadheading, encourages more vigorous flowering in many species. Because seed formation draws on the plant’s resources, removing them will allow the plant to direct more of its energy to continued flowering. While some plants respond to this with more additional bloom than others, removing old flowers will improve the appearance
of any display. Some varieties drop their old flowers on their own—these are called self-cleaning. Deadheading is most important to annuals, whose short lives demand that nothing inhibit flowering. Perennials and bulbs may be able to increase their food storage for next year’s bloom if you deadhead them, though this will not usually promote reblooming in the same season.DIVISIONMost perennials benefit from periodic division of their crowns (the underground portion of the plant, consisting of roots, stems, tubers or rhizomes). Some species grow best when you do this annually, while others may require it every 2 or 3 years. A few species are better off left alone. Because there is no way to generalize about frequency, you should familiarize yourself with the specific requirements
of each species for which you care. Division consists of nothing more than digging up the crown of the plant during dormancy and splitting it up into two or three sections, which you should replant immediately. Crowns may be pulled apart by hand, if possible. However, many species, especially those with woody or tough crowns, may require you to use shears or a knife to divide them. Divide spring and summer bloomers during the fall, after they have died back but before the onset of cold weather. Divide fall-blooming perennials in early spring, before they have started to push growth. Division is less stressful to plants during cool weather. Also, irrigate prior to division if the ground is dry.DISEASE CONTROLPlant diseases can and often do prevent bedding plants from performing well. However, certain basic steps will minimize the potential for disease outbreaks in your beds.The first step is to use only disease-free stock for planting.
This seems obvious enough, but bedding plants quite often harbor unnoticed diseases. It pays to inspect plants thoroughly before you buy them. Providing the best possible growing conditions for your bedding also minimizes disease problems. Healthy, vigorous plants resist disease much better than stressed plants. This means providing good water management (avoiding drought and saturated soil), adequate soil fertility
and structure, and proper spacing to allow for air circulation. Taking these steps will eliminate much of the potential for bedding diseases. However, problems still may arise now and then, especially when weather conditions favor them. When they do, you must take appropriate steps.• Inspecting plants before you buy them is an important step. Talk to other grounds-care professionals to find out which growers they recommend for providing disease-free bedding. Regardless of the supplier with whom you deal, always thoroughly inspect bedding you intend to purchase. For example, bacterial wilt of geraniums is a common
problem of vegetatively propagated geraniums. This disease is incurable so you must destroy any infected plants. Symptoms to look for include V-shaped yellowing PRE-EMERGENCE HERBICIDES FOR LANDSCAPE ORNAMENTALSActive ingredientBrands and suppliersBenefin + oryzalinXL 2G (Helena)BensulideBensumec, Pre-San (PBI/Gordon)Squelch (Opti-Gro)Corn glutenDynaweed (Soil Technologies)DichlobenilBarrier (PBI/Gordon)Casoron (Crompton Uniroyal)DithiopyrDimension (Andersons, Best/Simplot, Dow AgroSciences, Howard Johnsons)Lifeguard (LESCO)IsoxabenGallery (Dow AgroSciences, LebanonTurf)Isoxaben + trifluralin*Gallery+Team Woodace Preen Plus (LebanonTurf)Snapshot (Dow AgroSciences)Oxadiazon*Oxadiazon (Andersons)Ronstar (Bayer, Regal)Ronstar Woodace (LebanonTurf)Oxadiazon + napropamidePrePair (UHS)Oxadiazon + prodiamine*RegalStar G (Regal)Oxyfluorfen + oxadiazon*LaSar (UHS)Regal O-O (Regal)PendimethalinPendimethalin (Andersons)Pendulum (BASF)PRE-M (LESCO)ProdiamineBarricade (Andersons, Howard Johnson's, Syngenta)RegalKade (Regal)Stonewall (LESCO)S-MetolachlorPennant Magnum (Syngenta)TrifluralinPreen, Treflan (LebanonTurf) Treflan, Vegetable & Ornamental Weeder (Monterey)Treflan (Andersons, LebanonTurf)* These products’ primary use is for woody ornamentals. Check product labels for specific sites and species.
between leaf veins, leaf spotting and wilting.Viruses, mostly a problem on vegetatively propagated
bedding (impatiens or begonia, for example) can produce a variety of symptoms. Viruses are not curable. Thus, as with bacterial wilt, you must destroy any infected material. Symptoms can include malformed
plants or plant parts, stunting and yellowing. These symptoms might result from other conditions besides viral infection, but you should avoid such plants, whatever the cause. Other viral symptoms are more diagnostic, and include lines, concentric rings or other oddly patterned and colored designs on leaves. These are often quite distinct.• Root and stem rots. Root- and stem-rot fungi, such as Pythium and Rhizoctonia, reside in the soil. When spring arrives, they are primed to attack new transplants.
If enough moisture is available, and soil temperatures
are adequate for fungal activity, infection can quickly develop if roots or stems contact fungi. An important preventive measure is to ensure good drainage. However, if soil is already known to be infested, the best way to avoid root and stem rots is by treating the soil before planting to kill soil-infesting fungi. You should apply treatments when fungi are active and most vulnerable: when soil temperature at the 6-inch level is above 50°F and soil is moist. Fall is preferred, but spring also is appropriate if soil moisture and warmth are adequate.If a bed has a history of heavy infestations, fumigation
may be appropriate. Methyl bromide and Vapam
are products used for this purpose. Fungicides may be adequate if the planting has experienced only minor outbreaks. Plus, unlike fumigants, fungicides labeled for bedding applications may be applied after the plants are installed. Follow product-label instructions exactly. Fumigants in particular, but other chemicals as well, can be toxic to bedding plants if you apply them improperly or do not wait long enough after application to transplant.• Stem, leaf and flower pathogens typically require wet surfaces to infect plants. Symptoms generally consist of necrotic spotting on the leaves and, sometimes, stems. The same pathogens also may cause flowers to rot. In the section on irrigation, we mentioned the fact that some plants enjoy overhead watering, while others do not. Those that don’t often are those that are susceptible to splash-dispersed diseases. These include both bacterial and fungal pathogens and require wet surfaces to spread. Therefore, keeping plant surfaces dry and providing good air circulation are the keys to preventing or stopping these diseases. Some can be controlled with chemical applications, others cannot. Correct diagnosis is critical, and you should obtain a disease reference, preferably one with photographs, to aid you in diagnosis.Botrytis is a common bedding-plant disease. Petunias and geraniums are especially vulnerable, but many other species may be attacked as well. Botrytis thrives in humid, wet conditions and minimizing these factors should minimize this disease. Botrytis usually stops spreading once conditions are no longer favorable. Botrytis typically infects leaves and flowers, so when conditions improve, infected plants may recover. Also, a variety of fungicides registered for bedding are effective against Botrytis in case environmental conditions that favor the disease persist.Powdery mildew is another common disease of many annuals and perennials, especially later in the growing
season. Anti-transpirants provide a physical barrier against infection by powdery mildew. This is a tactic many growers use successfully. However, it is wise to test-spray a few plants to ensure they will not suffer any phytotoxicity. Again, fungicides are available for this POST-EMERGENCE HERBICIDES FOR ORNAMENTALSActive ingredientNon-selective2Selective for…1Liquid or granular?Brands and suppliersBroadleaves GrassesSedgesAmmoniated soaps of fatty acidsXLQuick Fire (Monterey) BentazonXXXLBasagran T/O (BASF)LESCOGran (LESCO)Nutgrass ‘Nihilator (Monterey)Cacodylic acidXLEcoExempt HC Herbicide Concentrate (Prentiss)Montar, Weed Ender (Monterey)CAMAXLSelectrol (Opti-Gro)CarfentrazoneXLQuicksilver (FMC)ClethodimXLEnvoy (Valent U.S.A.)Clopyralid2XLLontrel T&O (Dow AgroSciences)Dicamba4 XLDicamba (Tree Tech)Dichlobenil3XXGBarrier (PBI/Gordon)Casoron (Crompton Uniroyal)Diquat2XLAqua-Trim II (Opti-Gro) Reward (Syngenta) FenoxapropXLAcclaim EC (Bayer)Fluazifop-P-butylXLFusilade II (Syngenta)Ornamec (PBI/Gordon)Glufosinate-ammonium2XLFinale (Bayer)Glyphosate2XLGly-Flo (BASF)Gly Star Pro, Clear-Out 41 Plus (Agrisel USA)Kleenup Pro (UHS)Prosecutor, Prosecutor Pro, Prosecutor + Tracker (LESCO)Roundup Pro/Pro Dry (Monsanto)Touchdown Pro (Syngenta)Trail Blazer (Opti-Gro)Glyphosate + diquat dibromideXG5QuickPro (Monsanto) ImazaquinXXXLImage 70 DF (BASF)MecopropXLChem-Weed (Opti-Gro)MSMAXXLMultipurpose MSMA (Agrisel)Weed Hoe (Monterey)Pelargonic acid2XLQuik (Monterey)SethoxydimXLGrass Getter (Monterey) Vantage (Agrisel USA, BASF)1 Indicates general group for which herbicide is selective. Product may not be effective against all members of that group. Always check labels for listed species. 2 Registered in ornamentals for spot or directed spray only, unless otherwise directed. 3 Granular product for use in woody ornamentals.4 Trunk injection. 5 QuickPro is a water-soluble granule for mixing with water.
chapter 6disease if other measures are ineffective.• Bulbs are susceptible to many diseases. In fact, some diseases that infect bulbs are the same pathogens that infect annuals and perennials. Proper drainage, good soil conditions, air circulation and minimizing wet plant surfaces likewise prevent most disease problems. One situation especially harmful to bulbs is saturated soil. This can cause bulbs to rot if pathogens are present in the soil, as they often are. Fungal rots cause bulbs to be lightweight, soft, chalky, woody or dry and spongy. Bacterial
rots cause bulbs to be mushy, slimy and foul-smelling.
Plants so affected must be removed and destroyed. For future plantings, improve drainage and, if infestations are heavy, consider fumigation as discussed above.Bulb rots also occur in storage. There, too, good air circulation around the bulbs is critical. Remove excess soil from bulbs you recently dug from beds and let them dry for a day or so before storing them. Also, do not pile bulbs deeply. • Chemical treatment and disease identification. Many types of bedding diseases occur, some more commonly than others. Due to the variety of diseases you could encounter,
you may find it necessary to seek the help of an extension agent for accurate identification and treatment recommendations. A good ornamental-disease reference is often adequate, however. In general, providing good drainage, reducing surface wetness and allowing good air circulation and sunlight exposure are the best ways to minimize these diseases. But remember that if cultural
practices fail to prevent or reduce disease problems, fungicidal products are available for many ornamental diseases.WEED CONTROLWeed control is usually not a serious problem in bedding
displays. Because of frequent changeouts, perennial weeds do not typically get a chance to gain a foothold, and seedling annual weeds tend to lose out to transplants, which have a head start. A healthy bedding display forms a canopy so dense that most weeds cannot thrive. Those that manage to grow usually are few enough to be pulled by hand. Thus, beds that have been worked for several years usually are reasonably weed free. As discussed above, mulches are mainly of aesthetic value, but where the planting is thin or where weeds are unusually heavy, mulch may be beneficial as a weed suppressant.Hand pulling avoids the use of herbicides, especially pre-emergents, that can be problematic in annual beds. Even if safe on the current planting, herbicide residues can harm future plantings that include species sensitive to the chemical you use. This is not to say that pre-emergents are useless in color beds. Just be aware that you may be limiting your planting choices for future changeouts. Perennial
beds, of course, do not have this limitation. Just ensure the product is registered for the species present in the planting.In spite of this, certain situations call for herbicide use. You may be creating a new bed or you may have inherited
a weed-infested planting. If you are creating a new bed, be sure to use a systemic herbicide that provides a complete vegetation kill, such as glyphosate (Monsanto’s Roundup) or glufosinate (Bayer’s Finale). This will provide
a weed-free beginning.A pre-emergent also may be necessary in new beds until weed populations are reduced. In such cases, a number of products are relatively safe and effective (see “Pre-emergence herbicides for ornamental plantings,”
page 42). Selective post-emergence herbicides also are available for removing grassy weeds and sedges from broadleaf plantings. Unfortunately, selective post-emergence broadleaf control in most bedding is nearly impossible because broadleaf products also affect bedding plants (nearly all of which are broadleaf species).Spring-flowering bulb plantings often are less weed-prone than summer beds because they are installed just before cold weather. Still, spring weeds and, to a lesser extent, winter annuals, can be a problem. Spot treating with non-selective herbicides is effective in situations where such use is possible. However, herbaceous
plantings typically are so dense that the risk of drift is too great to chance. (See “Selective post-emergence
herbicides...,” page 42, for a listing of selective post-emergence products registered for use in bedding sites.) Always read and follow all label directions. They contain important precautions that could apply to your plantings. The products listed in the table are not labeled for every bedding situation, so make sure any product you intend to use is appropriate for your site. Also, it is a safe practice to make a test application on a small area before using a product on a wide scale.INSECT CONTROLInsect control is frequently necessary in herbaceous plantings. As with all stresses, healthy, vigorous plants are more tolerant than weak ones. When necessary, however,
do not hesitate to use control measures to quell a damaging infestation. The season is too short for most annuals to recover from significant damage well enough to provide a colorful show. See Chapter 16 for a discussion
of insect pests.IRRIGATIONFor information on irrigation systems and strategies for bulbs, annuals and perennials—as well as turf—refer to Chapter 9.
Turf Cultivation and Dethatching
Cultivating turf presents problems that are not encoun-tered in annual crops. Turf is a perennial cover, and you must take special care to prevent undue disruption of its surface characteristics when you need to alleviate a soil problem that occurs in it. Unlike row crops that you can plow, you want to keep your desirable turf intact while cultivating. Manufacturers have developed special techniques and equipment to do so. Technically speaking, aeration is the naturally occurring
process of air exchange between the soil and its surrounding atmosphere. Practically speaking, aeration —also called aerification—is the process of mechanically removing small plugs of thatch and soil from a turf area to improve soil aeration. Textbooks often refer to the practice of soil aeration as soil cultivation (coring, spiking
and slicing). The aeration process is also commonly called core aeration or simply aeration.WHAT ARE THE BENEFITS OF AERATION?Core aeration helps the lawn’s health and vigor, and it reduces maintenance requirements. The following are other benefits of core aeration:• Improved air exchange between the soil and atmosphere
• Enhanced soil-water uptake• Improved fertilizer uptake and use• Reduced water runoff and puddling• Improved turfgrass rooting• Reduced soil compaction• Enhanced heat- and drought-stress tolerance• Improved resiliency and cushioning• Enhanced thatch breakdown.The type of aeration equipment you use influences the benefits you’ll obtain from aeration. Equipment with hollow tines removes soil cores. Equipment with open, or solid, tines divots the soil surface.Aeration equipment varies in tine size up to 0.75 inch and in depth of penetration up to 3 inches, depending on the manufacturer’s specifications. Deep-tine aerators that penetrate much deeper also are available.Penetration depth depends on soil type, soil moisture, tine diameter, and the weight and power of the aerator. For example, tines penetrate sandy soils easier than they penetrate heavy clay soils, and penetration is better in moist soils than dry soils. In general, turf responds best when cores are close together and deep.A 0.75-inch aeration tine with 6-inch spacing and a penetrating depth of 3 inches removes about 1.2 percent of the soil’s volume in that 3-inch profile. The same tine spaced 2 inches apart removes about 10 percent of the soil in the same 3-inch profile. The closer tine placement
removes more soil, exposes more soil surface area for water and fertilizer uptake and alleviates compaction quicker than the wider tine spacing.WHY IS AERATION NECESSARY?In landscaped areas, the natural soil has been seriously disturbed by the building process. Fertile topsoil may have been removed or buried during excavation of basements
or footings, leaving subsoil that is more compact, higher in clay content and less desirable for healthy lawn growth. These lawns need aeration to improve the depth and extent of turfgrass rooting and to improve fertilizer and water use.Plug removal. Core aeration mechanically removes plugs of soil from turf. This technique reduces compaction of the soil and improves the ability of the roots to expand into the soil.Thatch breakdown. Core aeration modifies thatch by incorporating soil into it. This allows soil organisms to break down the thatch and reduce its accumulation. Turfgrass rooting and surface growth also improve after aeration.
Intensively used lawns are exposed to stress from traffic injury. Walking, playing and mowing are forms of traffic that compact soil and stress lawns. Raindrops and irrigation
increase soil density by compacting soil particles and reducing large air spaces where roots readily grow.Compaction is greater on heavy clay soils than on sandy soils, and it is greatest in the upper 1 to 1.5 inches of soil. Aeration helps heavily used lawns growing on compacted soils by improving the depth and extent of turfgrass rooting,
allowing better water uptake, enhancing fertilizer use and speeding up thatch breakdown.Most home lawns are subject to thatch accumulation. If thatch is left unmanaged, it can lead to serious maintenance
and pest problems. For example, thatch accumulation
of more than 0.5 inch on Kentucky bluegrass lawns impedes water, fertilizer and pesticide effectiveness. Core aeration reduces thatch accumulation, minimizes its buildup and modifies its makeup by incorporating soil into the thatch. As soil is combined with the thatch debris, soil organisms are better able to break down the thatch and reduce its accumulation.Thatch accumulates faster on compacted soils, heavy clay soils and subsoils that are disturbed during building processes than on well-aerated soils. Therefore, lawns require frequent aeration to prevent thatch buildup. Most home lawns growing on heavy clay or highly compacted soils require annual aeration to restrict thatch accumulation.
WHEN SHOULD LAWNS BE AERATED?Annual aeration is beneficial for most lawns. Lawns growing on heavy clay or subsoils, and lawns exposed to intense use benefit from more than one aeration each year. In general, benefits from core aeration increase when tine spacing is closer and penetration is deeper. Most turfgrasses respond favorably to aeration when it is properly timed.Both spring and fall are ideal times to aerate cool-season
turfgrasses such as Kentucky bluegrass and perennial ryegrass. In most cases, spring aeration is performed between
March and May, depending on the location, turfgrass
species and intensity of use. Fall aeration is done in late summer and early fall, usually between August and November. Aeration before or at the time of late-season fertilization enhances root growth responses and improves spring greenup and growth.It is best to aerate warm-season turfgrasses such as zoysiagrass and bermudagrass in mid-spring to summer. Avoid aerating when warm-season grasses are dormant. This may encourage cool-season weed competition. In addition,
avoid aerating warm-season grasses during spring greenup. It is best not to aerate warm-season lawns until after they have received their first mowing in spring.Turf authorities used to advocate that it is best to aerate Thatch buildup. Although a thin layer of thatch is beneficial, thatch accumulation should not exceed 0.5 inch. Excess thatch blocks air, light and water from reaching root zones. Core aeration reduces thatch accumulation and minimizes its buildup.Soil compaction. Turfgrass in compacted soil (left) grows slowly, lacks vigor and becomes thin or does not grow at all. Core aeration (center) removes small cores of soil, depositing them on the surface of the turf. This improves the depth and extent of turfgrass rooting (right), and it can help save money on your water bill.CUSEFUL DEFINITIONS• Compaction. A condition that occurs primarily in the upper 1 to 1.5 inches of soil. Compacted soils have reduced air spaces and more resistance to root growth than non-compacted soils. Compacted
soils are dense and allow water to puddle and run off.• Core aeration. The mechanical removal of small cores of soil and thatch from the lawn.• Dethatching. The process of removing the thatch layer from turf. This process is usually done mechanically with a dethatching unit or power rake. This equipment mechanically removes thatch with rigid wire tines or steel blades, which slice through the turf and lift the thatch debris to the surface for removal.• Thatch. The layer of dead and decaying plant tissue located between the soil surface and the green vegetation. A thin layer of thatch is beneficial because it reduces soil compaction and increases wear tolerance. However, a thatch layer of 0.5 inch or more prevents air, light and water from reaching the turf’s root zone. Thatch also makes an excellent breeding ground for harmful insects and disease organisms.
Abefore you apply pre-emergence herbicides, rather than after. They thought that aerating after an herbicide application
would reduce the chemical barrier formed by the herbicide, thereby allowing weeds to germinate and grow in the lawn. Current research, however, disputes this. Applying fertilizer after aeration helps the lawn compete against weeds. Water the lawn carefully after aeration, particularly in areas where drought and high temperatures are common. WHAT CAN YOU EXPECT?Immediately after aeration, your lawn will be dotted with small plugs pulled from the soil. Within a week or two, these plugs of thatch and soil break apart and disappear into the lawn.About 7 to 10 days after aeration, the holes will fill with white, actively growing roots. These roots are a sign that the turfgrass is responding to the improved soil oxygen, moisture and nutrients derived from the aeration process.On compacted soils and on lawns with slopes, you should see an immediate difference in water puddling and runoff after irrigation or rainfall. After aeration, your lawn should be able to go longer between waterings,
without showing signs of wilt. With repeat aerations
over time, your lawn will show enhanced heat and drought stress tolerance.Don’t expect miracles from a single aeration, particularly
on lawns growing on extremely poor soils. Most lawns benefit from annual aeration. Lawns that receive this care will be healthier, more vigorous, easier to maintain and have fewer pest problems than lawns that are neglected.TLDWATER-INJECTION AERATORSA major drawback to core cultivation is that the surface is temporarily impaired when the core is removed. This is a critical point on golf course greens that demand a good putting surface. Addressing this point, manufacturers
have developed water-injection cultivators. Water-injection cultivators aerify the soil by injecting pulsating, high-speed jets of water through nozzles spaced across a manifold bar. A water source is connected to the unit, and a high-pressure pump energizes the water before it shoots through the nozzles. Water speeds reach more than 600 miles per hour to fracture the soil as deep as 8 inches. Because the technique makes no coring holes, the surface is not appreciably disturbed and play is not unduly interrupted. You also can use water-injection cultivators to inject other materials, such as wetting agents.SLICERS AND SPIKERSYou use slicers and spikers for less intensive turf cultivation. Slicers and spikers are generally pull-type, non-powered units that consist of a series of discs mounted on a horizontal shaft. The edge of the disks may have V-shaped knives—in the case of slicers—or solid tines—in the case of spikers. The depth of penetration into the soil is dependent on the weight of the unit but usually does not exceed 2 inches. VERTICAL MOWING AND DETHATCHINGVertical mowers are wheeled, powered units equipped with a horizontal
shaft and fitted with vertically oriented blades. The shaft spins rapidly, and the blades slice into turf. Depending on the task you want to accomplish, you can adjust the shaft up and down on vertical mowers to cut more shallowly or more deeply into the turf. Vertical mowers are similar to flails in that the blades on both machines are vertically oriented. However, with vertical mowers, the blades cut into and through the turf. Flail-mower blades cut only to soil level.Thatch control is the primary reason for vertical mowing. If you have a thatch layer deeper than 1 inch, your best bet is to use a vertical mower to remove it rather than relying on other cultural techniques to reduce it. Even so, vertical mowers can take on a wide array of other tasks:• Slicing stolons and decumbent leaves to reduce grain• Breaking up cores (after core aeration)• Injuring ryegrass to aid bermudagrass competition during spring transition• Assisting with fall overseeding projects.Manufacturers offer a variety of vertical mowing equipment. Some triplex greens mowers, for example, offer removable reels you can exchange for vertical-mowing attachments. These units changeover in minutes simply by pulling pins and loosening bolts, then hooking up the new attachment. Many manufacturers also offer vertical-mower attachments for flail mowers, walk-behind greens mowers, fairway mowers and hydraulic-reel mowers. Other smaller vertical mowers use flexible-wire tines rather than steel blades. Larger, more specialized riding units also are available. These mowers often offer extra-capacity catch-boxes, which make it easier to remove debris during dethatching.
This task is a necessary, and often time consuming, part of the dethatching process.TURF CONDITIONERSAnother twist on the same idea as the vertical mower is the development
of turf conditioners (also called groomers). These units are similar to vertical mowers in that they have vertically oriented blades on a rapidly spinning, powered, horizontal shaft. The difference lies in the close spacing of the conditioners’ blades (down to 0.25-inch spacing) that are not intended to cut into the soil like a vertical mower. Conditioners
are specialized vertical mowers that you use to cut into a turf canopy and force plants to grow in a more upright position. These units are primarily used on greens and fairway bentgrass. You can purchase conditioners as accessory reels for green and fairway mowers. MORE AERATING & DETHATCHING EQUIPMENT
MowingFront-mounting provides easy visibility of the cutting units, but the extra weight may increase steering effort, reduce maneuverability
Once you’ve established turf, its routine mowing is your single-most important grounds-care practice. Mowing dramatically affects
the appearance of a landscape and the health of the turfgrass plants. And it is often the largest cost factor in maintaining any landscape.HEIGHT OF CUTOne of the most common turf-management mistakes homeowners
make is cutting turf too low and not frequently enough. They don’t necessarily scalp it to the bare ground, of course—just to the lower limit of tolerance. Their objective is to improve the turf’s appearance, but the result is often the opposite.After maintaining turf too low and cutting infrequently for a couple of years, you’ll find more weeds, more disease, more insects and generally poorer turf quality.Specifically, these results are caused partly from mechanical removal of too much leaf tissue and subsequent physiological effects
on the plant. Mowing cuts newly emerged, highly photosynthetic
leaf blades. This means older, less photosynthetically active
blades must carry the burden of carbohydrate synthesis for the plant. As a result, the plant weakens
and root growth slows as the plant-produced carbohydrates are shunted to produce new leaves. Turfgrass in this weakened state is not quick to recover from insect and disease injury. Weeds fill in the void.Proper mowing height is critical to turfgrass health because it:• Allows for proper food production
MMOWING HEIGHT STANDARDSMow turf to a height consistent with the use of the area and with maintenance standards. Here are general guidelines for turf maintenance
in various areas:# Improved areas. Cut turfgrass within the height range recommended
for the predominating grass in the mixture. Each type of turfgrass has a preferred mowing-height range, for example:Kentucky bluegrass 2.0 to 2.5 inchesTall fescue 2.5 to 3.5 inchesPerennial ryegrass 2.0 to 2.5 inchesBermudagrass (hybrid) 0.5 to 1.0 inchBermudagrass (common) 1.0 to 2.0 inchesZoysiagrass 0.75 to 1.0 inchSt. Augustinegrass 2.0 to 3.0 inches.On sports turf, you may need to modify these mowing heights according
to athletic-field use. For example, hockey fields and baseball infields require closer mowing. However, restore proper mowing height when these athletic seasons end.# Semi-improved areas. Cut semi-improved areas to a 3- to 4-inch height—an efficient cutting height for power equipment. Where weed control is a major problem, mow the area before weed seed matures. # Unimproved grounds. Mowing unimproved land is usually limited to minimum requirements for fire or weed control. Cutting heights are generally 4 inches or more, once or twice a year.COOLING EFFECTS OF HIGHER CUTTING HEIGHTS MEASURED ON A SUNNY DAYTiller, thatch, soil temperature (°F)1-inch mowing height2-inch mowing heightTimeIrradiance*Air temp Tiller Thatch Soil Tiller ThatchSoil12:30 p.m.698774698671681 p.m.101709375699271691:30 p.m.709175718972702 p.m.941709376718973702:30 p.m.729276729073733 p.m.889729476729273713:30 p.m.738975738373714 p.m.797738775738171714:30 p.m.738574737871715 p.m.656728074717470705:30 p,.m.727773717169706 p.m.47972767170696870*Irradiance: Sun intensity in watts per square meter reported as an hourly average. @Ambient air temperature 5 feet above ground. Source: Dr. Mark Welterlen.
• Reduces stress• Inhibits weed growth• Reduces irrigation requirements.But there is more to the story than this. By removing more leaf material and maintaining a lower canopy, you change the stand’s architecture and influence the turf canopy’s microclimate. More light reaches into the canopy, increasing turf and upper-soil temperature. Consequently, temperature of lower-cut turf is generally
higher than that of higher-cut turf.High temperatures speed up metabolism and can deplete carbohydrate reserves that turfgrasses need for growth. In addition, high temperature can interact with pesticides and cause phytotoxicity. Be aware that turf temperature may be quite different
than that indicated by a thermometer on the side of a building. You must consider actual conditions in the turf. Sunlight intensity is an important factor influencing turf temperature. On a sunny day, turf temperature may be considerably higher than on a cloudy day, even when the thermometer on the side of a building reads the same on both days.MOWING HEIGHT VS. FUNCTIONYou should select a mowing height based on turf’s function. Although each species has different mowing requirements, pay attention to turf quality and weediness
at each of the following mowing heights.# 1.5 inches. Most of the major cool-season turfgrasses
require mowing every 6 to 11 days. The quality
of these turfgrasses at 1.5 inches is typically below an acceptable level (6 on the table “Mowing requirements
of cool-season turfgrasses,” above), and weed cover is often high.You should not use cool-season turfgrasses in the transition zone when water is restricted and mowing height is 1.5 inches or less. Cool-season grasses often decline in this situation, and weed cover often dominates.
# 2.5 inches. Increasing mowing height from 1.5 to MOWING REQUIREMENTS OF COOL-SEASON TURFGRASSES1.5-inch mowing height2.5-inch mowing height4-inch mowing heightDays between
(DBM)Turf quality (6=acceptable)% weed coverDays between mowing (DBM)Turf quality (6=acceptable)% weed coverDays between mowing (DBM)Turf quality (6=acceptable)% weed coverFlyer spreading fescue74.66096.521157.66Dawson creeping fescue84.871136.639147.58Shadow chewing fescue85.352127.210177.81Aurora hard fescue115.252147.220228.04Bighorn sheep fescue105.646146.916188.08KY-31 tall fescue65.84687.411107.58Rebel tall fescue75.745116.623147.42Merion Kentucky bluegrass95.264156.442176.815Park Kentucky bluegrass65.655106.725117.07Pennifine perennial ryegrass75.257125.858245.652Beaumont meadow fescue65.15776.042126.219Reubens Canada bluegrass93.962165.628186.123Lincoln smooth brome42.39363.978104.933Napier orchard-grass32.49453.88064.666Weeds (mostly crabgrass)63.999103.899173.799Source: Dr. David B. Minner (University of Iowa, research done at University of Missouri—Columbia).
.5 inches generally reduces mowing requirements by about 5 days between mowing (DBM) with acceptable turf quality. For example, according to a study by Dr. David Minner
when he was at the University of Missouri—Columbia,
chewings fescue and sheep fescue required the least mowing (12 to 14 DBM) with modest weed infestation. KY-31 tall fescue had 11 percent weed cover, but its rapid growth resulted in an 8-day mowing
interval. With turf-type tall fescue such as Rebel, Minner was able to extend mowing from 8 to 11 DBM. But, he discovered, there was a trade-off between less mowing and more weeds with KY-31 and Rebel.# 4 inches. At a 4-inch mowing height, most cool-season turfgrasses require mowing every 10 to 24 days.FREQUENCY You should base mowing frequency on the growth rate of the grass, not on a set time schedule. Though this is easier said than done, it is the best practice.Mowing frequency typically varies based on the turf’s use and location. For example, a golf course typically mows its golf greens on a daily basis, while you only may need to mow a roadside several times a year. For most moderately to intensively cultured turf areas, the best advice is to remove no more than one-third of the turf height at any one mowing. If you remove more than one-third, you may create an imbalance
between aerial shoots and roots, thus retarding growth. Plus, too-frequent mowing can cause less rooting, reduced rhizome growth, increased shoot density, decreased shoot growth, decreased carbohydrate
reserves and increased plant succulence.Mowing according to the turf’s growth rate may mean you’ll mow more frequently during part of the season and follow a reduced schedule during other months. Weather conditions, irrigation and fertilization
also affect turf’s growth rate.When preparing to mow, adjust the mower to the proper height for the primary species of turf. If grass has grown more than normal since your last cut, don’t mow it to its normal height. Instead, increase the height of cut and gradually return it to the normal cutting height over a period of several weeks. If you cut excessively
tall grass down to its normal mowing height, you can severely damage it, especially during warm weather. Doing so removes most of the leaf area, leaving
primarily stemmy turf. This is less dense and more susceptible to invasion by weeds. Therefore, mow often enough that you do not remove more than one-third of the leaf blade. Regular mowing controls weed growth and encourages the development of dense, sod-forming turfgrasses.Ideally, you should allow turfgrasses to rest between mowings. Research has shown that when bentgrass was given 2 or 3 days to recuperate between mowings, vigor increased. This is because regrowth vigor is related to the photosynthetic potential of the clipped plants and their ability to use stored carbohydrates, both of which increase when some recuperation time is allowed.CLIPPINGSThe commercial turf industry creates more than 3.5 million tons of clippings a year, according to 1990 U.S. Environmental Protection Agency (EPA) statistics. Grass clippings can account for 20 to 50 percent of the residential solid waste added to municipal landfills each week during the growing season. As a result, while some turf managers still choose to bag clippings, many are finding it hard to dispose of them. Many states, in fact, have banned or are planning to ban yard waste (grass, leaves and tree and brush trimmings) from their landfills.Many industry experts say that bagging will become obsolete not only as a result of environmental concerns but because of the financial burden clipping disposal presents. A spokesman for the National Solid Wastes Management Association says mulching is increasingly
becoming one of the most feasible options for grass-clipping disposal: “The most inexpensive method of clipping disposal is to leave them on the lawn. Pay more, and you can haul the clippings to a separate composting facility. You can also pay to dump them in a landfill—if you can find one that will take yard waste.”If you are considering collecting and disposing of clippings through composting, keep in mind that this method is not cost-free. Bagging clippings places greater wear on machinery. In addition, collecting clippings and delivering them to the compost site takes increased time, labor and fuel and is an overall inconvenience,
especially for smaller crews. Educating and convincing customers about composting may take time as well. Finally, if you do not properly aerate or water your compost pile, it will not mature properly and can develop odor, which can make it hard to find a location
on which to place a composting site.Even more costly is the use of a centralized composting
facility. Fees at these sites are rising because the number of landfills is shrinking.Finally, some operators use side- or rear-discharge mowers without the bags and leave clippings on the
lawn. However, many in this market will not tolerate such excess clippings. For example, you must regularly
collect clippings if you care for golf-course greens—not only for aesthetic reasons but also because their removal prevents interference with the ball. Plus, some commercial customers demand bagging clippings
because they also prefer a more aesthetically pleasing appearance.Obviously, you can’t avoid collecting clippings if you mow golf greens and other similar turf areas. In these cases, though, collecting is really not that significant
of a problem. The clippings are minuscule in length, and most golf-course superintendents simply spread the clippings onto rough areas. However, if you have customers who would really prefer that you collect
the clippings, try to convince them to discontinue bagging by describing the many benefits of leaving the clippings on the turf.Leaving the clippings can add as much as 1 pound of nitrogen per 1,000 square feet seasonally. That can mean a 25 to 35 percent reduction in total fertilizer applied annually. Other studies have shown that, when you bag clippings, you remove about 100 to 150 pounds of nitrogen per acre every year.You’ll gain not only agronomic benefits from returning
grass clippings to the turf, but you can reap other savings, too. For example, a waste-reduction study in Florida showed that commercial participants who recycled clippings saved as much as 50 percent in mowing time and, as a result, used 50 percent less fuel. They also reduced labor costs and tipping fees to landfills and placed less wear on their equipment, especially on the bag side of the mower, which carried the extra weight.THE BENEFITS OF MULCHING MOWERSAlthough you can use a side- or rear-discharge mower to throw clippings back onto the turf, a mulching
mower is really your best choice. These units are specially designed to cut clippings into smaller and smaller pieces so they will easily fall back to the soil, rather than sitting on top of the newly mown turf.Unlike past units, today’s mulching mowers offer a much better-looking and more consistent quality of cut in a variety of conditions. Like any evolving tool, the degree of improvement has hinged on critical design elements. How air is managed under the deck dictates when, where and how the clippings will exit. Therefore, air-flow management is a pivotal feature in today’s mulching units and a key factor in determining
a unit’s effectiveness.In general, the units that have provided the biggest improvements incorporate a deck, cutting chamber and blade design that manage clippings better than older units. Skeptics remain, but these more sophisticated
units do create adequate suction to “stand” the grass, cut it, hold it long enough to chop it into tiny pieces and then evenly blow it into the turf without clumping. The subtle design of the individual cutting chambers and the blades inside the deck housing play a critical role in this process.EQUIPMENTChoosing the right mower for specific grounds-care conditions can be confusing because you have literally
dozens of models, types and sizes from which to choose. As you compare mower options, keep the following
criteria in mind:• Type of grass• Height of cut• Mowing frequency• Area use• Total area to be mowed• Obstacles present• Safety of operator and bystanders• Skill required for operation and maintenance• Skill level of operators and maintenance personnel• Economics• Equipment versatility.Evaluate equipment choices on the basis of performance
and cost, not on the purchase price alone. Cost considerations include the price paid for the equipment plus the cost of fuel, oil and lubricants, operating labor, parts, labor to make repairs, insurance and interest—less any trade-in value—for the expected life of the machine. You then should apportion the cost to the total area cut by the machine during its useful life and compared to similar costs per acre of alternative mowers.
Buy quality. Although it may be tempting to buy lower-priced homeowner models for large areas, professional
users may cover several times as much ground annually as the average user, resulting in accelerated wear and increased maintenance.FEATURES TO CONSIDER# A good range of operating and transport speeds. You want your mower to match the terrain and density of vegetation. A variable-speed drive—mechanical or hydrostatic—or an on-the-go, high-low shift can permit slowing to cut close to obstacles without reducing blade speed, which can cause poor cutting.# Easily adjusted cutting height and other settings. These aspects are important because you’re more likely to perform
necessary adjustments if they’re easy to make. Plus, an easier job is usually a quicker job, thus saving time. Blades should be easy to sharpen or replace and should hold a sharp cutting edge. A good range of height adjustment allows the operator to match varying lawn conditions and terrain.# Transport considerations. Consider also the number of crew members needed to load and unload your equipment,
as well as the ability of larger mowers to reduce to safe, legal transport width for movement on roads or streets and through narrow spaces. If the mower is front-mounted, does it block the operator’s view when raised to full height? Will it lift high enough to cross curbs and work around similar obstructions?# Flexibility. The mower should be able to follow ground contours without scalping and to cut close to obstacles to reduce later trimming. Mower ends and shielding should be smooth and preferably rounded to reduce damage in case of contact with trees, shrubs or other objects.# Adequately shielded drives and blades. The mower should meet all current safety requirements. Liability for possible
injuries could be blamed on the purchaser if equipment that fails to meet safety requirements is knowingly bought and placed in service. This also applies to use of rollover protective structures (ROPS) for tractors and larger mowing units. Law requires such protective devices and shields on some vehicles and equipment.# Adequate power. You want to prevent lowered productivity
from downshifting or frequent stopping when cutting heavy growth or traveling up an incline. However,
too much power may overload equipment and cause rapid wear or premature machine failure.ENGINES, OPTIONS AND MAINTENANCEA choice between 2- and 4-cycle engines is usually available, particularly on smaller mowers. On 2-cycle engines, you don’t have to check oil because the lubricating
oil is mixed with the gasoline. In fact, with these units, engine oiling is assured even when you operate the equipment on steep slopes. However, you must mix oil with gasoline in the proper proportions, a step that can lead to fuel contamination if you mix carelessly.With 4-cycle engines, you have no oil-fuel mixing. However, you must periodically change or add engine oil.Whether you choose a 2- or 4-cycle engine is up to you. One type is not necessarily better than the other. When operated as recommended, either should provide satisfactory service.Similarly, a choice of gasoline or diesel engines may be available. Diesel engines generally produce more work per gallon of fuel consumed, usually last longer, will lug down better and require no regular tune-ups. However, diesel engines are usually heavier than gasoline engines of equal power, which can be a problem
on soft turf. The initial cost of a diesel engine is nearly always higher, and diesels are more troubled by contaminated fuel.Compare also the maintenance requirements of different
mowers. Some mowers need more greasing and other regular attention, but certain options may reduce maintenance. Some walk-behind mowers, for example, offer an air-intake extension hose that draws and filters
air from the handle area so that the engine doesn’t pull in the heavy dust and dirt from around the engine. This feature helps reduce engine wear and should extend filter-cleaning intervals. A larger fuel tank option
can extend operating periods and reduce time wasted in refilling the tank.Increasing the number of blades and sections of a mower, regardless of type, usually improves uniformity
of cut, particularly if the mower can flex over uneven terrain. Similarly, many reel mowers are available
with different numbers of blades on each reel to match cutting ability to turf conditions. Some reels also are reversible to permit easy clearing of foreign objects or slugs of plant materials and for easy back-lapping. However, the addition of each extra blade, joint or other component increases mower complexity,
cost and maintenance. Choose the simplest mower
capable of providing satisfactory cutting of the area involved.Flail mowers, with many knives mounted on a horizontal shaft, avoid the windrowing problems of many rotary mowers. They also can handle wet grass better than most rotaries because the discharge area runs the full width of the machine. Because of the lighter blades that are generally free-swinging, the slower blade speed and the housing shape and normal trajectory of cut material, you usually have less danger of solid objects being thrown from a flail mower than from most rotary units. Therefore, some people suggest that flail machines are better suited for areas with heavy trash or where there may be large numbers of bystanders. You also can reverse some flail mowers (with blades swung forward at the bottom and up in front) for closer cutting of fine lawns. The greater number of cutting blades on flail mowers requires more maintenance and may increase the cost per foot of cutting width compared with most rotary mowers.
and possibly reduce visibility when raised for transport. Power units designed for front-mower attachment rarely have these problems.Mid-mounting provides excellent maneuverability
and good visibility. On tractors, it usually makes mower attachment and removal
more difficult, but it is of less concern with single-purpose mower power units.Rear-mounted mowers are usually easiest to attach and remove if you use the regular tractor
3-point hitch. Plus, your costs are reduced because of the absence of special mounting brackets or transport wheels, as well as direct connection to the tractor PTO. However, rear-mounting means low mower visibility.Trailing mowers are usually the simplest to attach or remove. However, trailing mowers have the lowest operator visibility, and maneuverability
can be a problem in tight areas. They also have the added cost of a hitch and transport wheels.THE NEWEST MOWER OPTIONThe newest entry into the mower market is the battery-powered mower. These mowers are gaining in popularity due to their low noise levels. The only commercial units available
are for mowing golf-course greens. However,
several consumer riding models are available, as well as an increasing variety of consumer walk-behind units.These units have their limitations, of course. Powered by lead-acid batteries, the commercial
greensmowers have a limited operating time before power runs out. You then need to recharge them overnight. They run for about 3 hours depending on temperature, terrain, battery age and other factors. Other considerations
with these units include battery life, battery use (and abuse) and weight. (The batteries
themselves are relatively heavy, which adds to the weight of the vehicles and thus reduces their driving range. Oversized tires have helped to compensate for this aspect.) As for the consumer units, they run on batteries
ranging from 12 volt to 36 volt. These units can cut from a quarter acre to 2 acres OVERALL SAFETY# Read the operator’s manual before using the equipment. Know where the controls are and what they do.# Know what the safety features are and how they work.# Operate and maintain the equipment according to the manufacturer’s
recommendations for safety.# Allow only individuals trained in safe operating procedures to use mowers.# Do not disable safety devices.# Know how to quickly stop the machine.# Dress properly. Wear heavy-duty shoes with non-slip soles, long pants and close-fitting clothes. Restrain hair and wear nothing
loose or dangling that could get caught in a moving part.# Fill the gas tank when the engine is cold. If you must refuel while working, let the engine cool off first. Wipe off any spills.# Do not smoke or light matches while filling up.# Clean up the area before mowing. Remove rocks, golf balls, twigs, toys—anything that could injure bystanders as it flies out the discharge chute. Always discharge clippings away from people. # Turn off the engine and disconnect the spark plug wire before working on the mower or attempting to unclog it.# Shut off the engine when adjusting mower height.# Periodically inspect the mower for potential hazards, such as loose belts, missing or damaged guards or safety equipment and accumulations of grass, leaves, grease or other debris that could become a fire hazard.# Keep hands and feet away from moving parts.# Mow when light is sufficient for you to see what you are doing. Keep a look out for debris 3 or 4 feet ahead. If you find any, pick it up rather than mow over it.# Do not operate equipment under the influence of alcohol or drugs.# Watch out for children entering the area. Mowing activities can be particularly attractive to children. But children often don’t have the common sense to stay at a safe distance.WALK-BEHINDSAFETY GUIDELINES• Never mow wet grass. You may slip, plus the grass is likely to clog your mower.• Mow across a slope and watch your footing. By mowing across the slope, you will be less likely to slip under the mower. Also the mower can’t roll back on you. Never mow a slope that is too steep to keep your balance or to control the machine.• Don’t overreach. Keep the proper footing and balance at all times.• Always push the mower; don’t pull it toward your feet.• Keep the mower flat; don’t lift the front end over tall grass or weeds.• Turf off mower blades when crossing a sidewalk or drive, especially those composed of gravel so that you don’t spray debris at passersby.• Take care when changing mowing directions to ensure no one has inadvertently moved into your path. Especially watch for children.• Immediately stop and turn off the mower after hitting an object.
Inspect the mower and repair any damage before resuming work.
before needing recharging. Recharging usually takes overnight (about 12 hours).Despite their limitations, battery-powered units have many advantages. Their maintenance is minimal, for one. The main advantage that most grounds managers see with these units, however, is their low noise levels. Golf courses situated in residential areas have been particularly interested in the mowers. (Admittedly, some gas-powered units are reaching new noise-level lows, too.) And even the consumer battery-powered units have found homes on sites where grounds managers must mow near vacationers or near hospital windows.
SHARPENING BLADESIf you don’t sharpen your mower blades regularly,
then you’re probably shredding turf rather than cutting it. When this happens, you end up with discolored grass that needs more time to recover. In addition, you put excess strain on your mowers’ engines, because they need greater horsepower to rotate or turn the blades.SHARPENING ROTARY MOWER BLADESA rotary mower’s cutting edge varies in length. Usually it is several inches long. Even so, only the first inch does most of the cutting, so it’s important
that you keep this area neatly sharpened. A razor-sharp edge is not necessary, however. In fact, an extremely thin blade wears rapidly. Also, stones or other debris can too easily damage an extremely
thin blade. Therefore, most experts recommend
leaving a slightly thickened edge on rotary blades.If you mow often in dry sandy conditions, you may need to check your blades more often. These conditions can cause blades to wear prematurely.
þ Step 1: Check the blade. Before you check your blade, shut off the mower’s engine and remove the ignition key. Detach the spark plug wire so that you can’t accidentally start the engine while you are working on the blade. Remove the blade from the deck (see Figure 1, above right). Check to make sure it is whole with no bends, cracks or other damage. You cannot safely straighten a bent blade. You must replace it. Likewise, replace the blade if it appears that the area where the sail and the flat part of the blade meet is cracked (for identification of a blade’s parts, see Figure 3, right). The sail is the slightly upturned, non-cutFigure
1. Remove the blade from the mower deck. Make sure you’ve disconnected the spark-plug wire before doing so. Then check the blade for chips, cracks, bends or other damage.Figure 2. Take out any nicks first, then sharpen the blade following the manufacturer’s recommended angle and grinding pattern.Figure 3. File off any leftover rough edges with a hand file.Sail(or heel)TipCutting edgeFlat part of blade
2004 # TURF & LANDSCAPE DIGEST 55
Figure 4. Place the blade on a balancer to ensure its weight is properly distributed. If the blade does not remain horizontal on the balancer, you’ll need to go back and grind each end of the blade until it is evenly balanced.SAFE RIDING-MOWER USE• Never carry passengers.• Do not mow in reverse unless absolutely necessary. If you must mow in reverse, stop before shifting, then watch behind you the entire time you are moving.• Never leave an unattended machine running. Always turn off blades, set the parking brake and stop the engine before dismounting.
• Stop the engine before removing the grass catcher or unclogging the chute.• Turn off the blades and attachments when not mowing.• Watch traffic when crossing or operating near roadways.• Watch for holes, ruts, bumps or other uneven terrain that could overturn the mower.WHEN MOWING SLOPES,FOLLOW THESE RULES:J Mow up and down slopes because riding mowers can easily tip over.J Use slow speed and keep all movements slow and gradual.J Shift into a lower gear before mowing a slope. The gear should be low enough that you don’t need to stop to shift again while mowing
the slope.J Follow the manufacturer’s recommendations for wheel weights or counterweights to improve stability.L Do not start or stop on a slope. If tires lose traction, disengage the blades and proceed slowly down the slope.L Do not use grass catchers on steep slopes or rough terrain. If you must turn on a slope, disengage the blades, then slowly and gradually turn downhill.L Do not mow near dropoffs, ditches or embankments where a wheel could go over the edge or the edge could cave in and tip over the mower.ting, back edge of the blade. If a slot forms in this area, a piece of the sail could break away while you mow and injure you or someone else. If the blade appears whole and in good shape, clean it well. Remove all excess mulch.þ Step 2: Grind out nicks. You can remove nicks and sharpen dull blades using a variety
of techniques. Use a grinder, hand file or an electric blade sharpener (see Figure 2, page 54). (Be careful not to overheat the blade. You can recognize overheating by the blueing spots that appear on the blade. This ruins the blade’s temper and durability.) Position the upper side of the cutting edge against the grinding edge and move it back and forth. Grind only the top surface of the blade. If you grind the blade’s bottom, you will create a chisel shape. This will push the grass down. The blade tip also should be straight, with the cutting edge lower than the sail (also known as the heel). A twisted blade with the sail lower increases the engine’s power requirement and does not allow the blade to cut evenly.þ Step 3: Grind the angle. Follow the manufacturers’ guidelines for the proper angle and grinding pattern, or simply maintain
the original bevel. Firmly move the blade into the grinding area while moving the blade back and forth along the length of the cutting edge. Continue this motion until you have sharpened the blade sufficiently.
þ Step 4: Sharpen the other end of the blade next. Remove the same amount of material from each cutting edge to try to keep the blade balanced.þ Step 5: File the edges. After you’ve got a good edge on the blade, file the back side to remove any rough edges that are left over from the sharpening process (see Figure 3, page 54).þ Step 6: Balance the blade. A blade must be balanced before you can return it to the mower. To check, place the blade on a balancer
(see Figure 4, above), or clamp a screwdriver horizontally in a vice and rest the center of the blade on that. A balanced blade will rotate so that the heavy side falls. The rate of fall shows how much out of balance the blade is.þ Step 7: Grind the blade end to balance.
56 TURF & LANDSCAPE DIGEST # 2004 chapter 8
If you need to remove weight from one side of the blade to balance it, grind off the outer end of the blade tip rather than the cutting edge. You typically can balance the blade with no more than three balance checks and two correction grindings.þ Step 8: Re-install the blade. Re-install the blade onto the deck. Make sure that you position it properly
and that the cap screws or nuts are properly torqued. An improperly installed blade can cause severe
vibration and might work loose or break during operation.SHARPENING A REEL MOWER'S BLADESReel mowers were common long before rotary mowers
became popular in the 1950s. Reel mowers’ acceptance
continues to last despite the machines’ many drawbacks. For example, they generally cost more than rotary mowers; they are more difficult to use; they have limited capabilities; and they are more complex to maintain. Reel mowers endure, however, because they produce a superior cut—especially at low mowing
heights.Reel mowers perform their job by the reel shearing individual grass blades as they contact the bedknife. The action is similar to a pair of scissors cutting paper. This technique differs greatly from the swinging-machete
action of a rotary blade.While a rotary mower with a severely dull or bent blade will continue to cut grass, this is not true of a reel mower. If the reel does not properly meet the bedknife, the machine will not cut. You make reel-to-bedknife adjustments by one of two methods. Some machines have a stationary bedknife, and you simply move the reel by turning an eccentric bearing plate on each end of the reel. Others have a stationary reel, and you move only the bedknife by turning adjustment screws at each end of the bedknife. When you no longer can adjust the cutting surfaces so that they meet, you must replace either the reel, the bedknife or occasionally
both. This situation typically develops after many sharpenings have removed much material from the mating surfaces.How do you know when to sharpen—or back lap—your mower’s reels? Look for the following conditions:
• Mowed grass looks uneven. This is a result of severely rounded reel blade and bedknife edges. • Mowing leaves streaks of uncut grass. This condition results when one or more reel blades are bent, leaving too much clearance between the reel and bedknife. It also can result from reel blades or bedknives that are severely
or unevenly worn.• Mowed areas are higher at one end of the cut than the other. This condition results from a cone-shaped reel.þ Step 1: Find out whether you need a back-lapping machine. Refer to your mower’s instruction manual to determine whether you need a back-lapping machine
or whether you can perform this task without one. If a machine is necessary, first attach the cutting unit to the back-lapping machine. Elevate the cutting unit at the rear so the lapping compound flows onto the lip of the bedknife through the back-lapping process.
If you don’t need a back-lapping machine, simply follow
the steps below and turn the blade backward by hand.þ Step 2: Apply a water-soluble lapping solution. A water-soluble solution is easiest to remove. Apply it with a 2-inch brush.þ Step 3: Turn on the back-lapping machine. Allow the reel to turn in the reverse direction for about 3 to 4 minutes. If the blades still aren’t sharp, continued back lapping will not solve the problem because most likely the bedknives are worn or flat, or the reel-to-bedknife adjustment needs actual sharpening.þ Step 4: Clean off the lapping compound. After back-lapping, whichever method you use, thoroughly clean the compound from the cutting surfaces to prevent
premature wear and dulling.þ Step 5: Grind the bedknife if needed. Several different
brands and types of machines are available to perform the sharpening process. Two basic designs exist. Either a carriage assembly moves the bedknife or reel back and forth past a stationary motor and grinding wheel, or the motor and grinder shuttle past the stationary mower parts. The basic principle remains
the same for both.Follow your grinder manufacturer’s instructions for mounting the bedknife or reel in the grinder. Improperly
placed or secured parts can lead to cone-shaped reels or chipped or broken grinding wheels.Next refer to your mower manufacturer’s instructions
to find at what angle to grind your reels. Some mowers require you to grind the reels on the blade’s edge, while others are designed with a relief angle on the backside of the blade.Remove the bedknife and attach it to the bedknife grinder.þ Step 6: Adjust the grinder. Before you turn on the grinder, move the carriage back and forth and adjust the wheel to lightly contact the highest point on the edge to be ground. (Heavy contact can result in heat buildup that causes an uneven bedknife surface.)þ Step 7: Move the carriage back and forth in slow, smooth passes. Don’t expect the grinding wheel to
2004 # TURF & LANDSCAPE DIGEST 57
TLDcontact the full length of the bedknife at first. Look for bright sparks that travel 1 to 2 feet. Dull sparks that travel only a short distance may mean you need to dress the wheel.þ Step 8: Don’t stop the carriage while the grinder is contacting the cutting edge but make adjustments throughout the process as needed. Continue grinding until the cutting edge is sharp, checking the edge by sight and feel.þ Step 9: Replace the bedknife on the mower. Now you can prepare to grind the individual reel blades.þ Step 10: Check for any movement—either radial, axial or end play—in the reel bearings. Next repair or replace any broken blades. Then tighten loose fasteners to the recommended tightness. Finally, clean dirt, dust and debris from each reel blade.þ Step 11: Attach the reel to the grinder. For spin grinding, first make sure the alignment is correct by using an alignment tool or gauge, or you may accidentally
grind the reel into a cone shape.þ Step 12: Measure the reel. After you have finished grinding across the entire length of the reel, measure both ends of the reel to ensure it is a true cylinder.If your mower requires relief grinding, procedures are slightly different. Use some type of marker (such as chalk) to mark the flat edge of each blade and to number each blade. Position the grinding wheel and follow your mower’s instruction manual as to the relief angle recommended.þ Step 13: Back lap again. Once you’ve finished grinding
your reel blades, some authorities recommend back lapping them. Doing so establishes a contact area on the blades, which in turn ensures the proper match between the bedknife and the cutting edges.Though performing such maintenance tasks may be time consuming, remember that preventive maintenance is the least expensive type. If you expect your machines to take care of your needs, you must take care of their needs.SPIN GRINDING VS. RELIEF GRINDINGSome reel sharpeners offer features and methods to accomplish a complete regrind that includes single blade relief and spin functions. Others don’t, so the debate between spin grinding only and spin plus relief has emerged as a hot topic — as is the comparison of “scything”
vs. “scissor” actions. Spin grinding alone produces a sharp cutting edge and is often compared to a scythe, which produces a good quality of cut as long as it remains sharp. Keeping the reel sharp can require the time-consuming
task of regrinding during the busy periods of summer. If the reel blades are not maintained to a sharp edge, then the bed knife must be kept sharp by facing or filing the front edge of the bedknife. With no relief, the reel blade thickness could cause increased drag as debris is brought between the reel and bed knife. A gap of one to two thousandths of an inch is recommended
between the reel and bed knife when you spin grind alone.On the other side of the debate, if you add a relief grind or grind the back side of the reel blade off as to produce a very thin land area, you can adjust the reel to the bed knife with virtually zero clearance between the two. With new varieties of ultradwarf turf and heights of cut well below 0.100 of an inch, you can measure the amount of leaf tissue being removed only in microns.A scissor action is attained when the reel in conjunction with the bed knife creates a shearing type action. Just like a pair of scissors, the two blades must be maintained extremely close to each other, so close that measuring would be impractical. The natural juices in the grass blades act as a lubricant and actually keep the reel blade and bed knife at near zero contact. If you want to have increased performance, you can do so by making the reel blades thinner by relief grinding, that is, by grinding away the backside of the blades.MOWING SAFETYMowing is serious business. In 2002, about 230,000 people were treated in hospital emergency rooms following
injuries related to various lawn and garden tools, according to the Consumer Product Safety Commission (CPSC). Each year, about 75 people are killed and about 20,000 are injured on or near riding lawnmowers and garden tractors. One out of every five deaths involves a child. CPSC estimates that most of the deaths to children occurred
when a child was in the path of a moving mower.
“No parent wants their child to be one of these statistics,”
said CPSC Chairman Ann Brown. “Young children move quickly and are attracted to mowing activity, but they don’t understand the dangers it poses. Parents should keep young children away from any outdoor power equipment.” The CPSC safety standard for walk-behind mowers has substantially reduced the number of mower injuries. In addition, CPSC has worked with industry on a standard for riding mowers to stop the blade if the rider gets off or falls off the seat.To prevent you or your crew from becoming a statistic, you should be aware of safe practices for operating mowers. You’ll find advice from the Outdoor
Power Equipment Institute (OPEI) and the CPSC for safe mowing practices in the boxed information that appears on pages 55 and at right. Make sure you understand this information. And train your crew to always follow these safety procedures.
Water is important to the growth and survival of plants. Water comprises 70 to 85 percent of the fresh weight of most turfgrasses
and landscape plants. It also functions as a transport medium and cooling mechanism
and is involved in many biochemical reactions in plants. As water is lost from evapotranspiration (ET) and leaching, you must apply more water to maintain a constant
supply to turfgrass and plants. Landscapes receive water from two sources: precipitation and irrigation. Some water moves upward through the soil profile to replenish water losses, but this process is normally too slow to meet turf needs. The best way to achieve a constant,
reliable supply of water is to irrigate.IRRIGATION NEEDAn in-ground, automated irrigation system makes life much easier for anyone who irrigates. Unfortunately, the convenience of time-clock irrigation promotes poor watering practices. Often, a technician sets the time clock at installation, and it remains at that setting thereafter. As a result, the automated cycle doesn’t accommodate the landscape’s actual water needs.Plant water requirements vary, depending on the species,
environmental conditions and cultural practices. These factors, which include relative humidity, day length, temperature, wind speed, mowing height and fertilization,
influence ET.Transpiration is the process by which turf and other plants absorb water from the soil and transport it from roots to leaves to the atmosphere. By monitoring transpired
water and water evaporated from the soil, you have a fairly good indicator of how much water plants use each day.Because both environmental and cultural factors influence
ET, water use is never constant. For example, in a study at Kansas State University, tall fescue ET ranged from 0.13 to 0.42 inches per day between July and August. This variability of turf ET emphasizes the importance of adjusting irrigation amounts to meet current demand. It also demonstrates that you can save water and improve irrigation efficiency by monitoring turf water use.FREQUENCYYou should only irrigate your landscape when it needs it. Ideally, you should irrigate when the first symptoms of wilt appear. Wilt is the visible loss of turgidity expressed
by drooping, folding or rolling of leaves. You can first detect wilt in turfgrass by a blue-green or slate-colored
appearance. “Foot printing” or loss of elasticity of turf is another visual symptom of wilt. Allowing turf to proceed through the wilting stage and into a more severely
stressed condition may result in summer dormancy
or, in extreme cases, turf death. Irrigating at the onset of wilt may not be practical in all cases, because landscapes may be in use during the day and cannot be irrigated without interrupting use. In such cases, you must use other methods to predict water need, for example the consumptive-use method or soil-moisture measurements. The consumptive-use method estimates ET from a turf stand (see boxed information, “Determining landscape-irrigation requirements,” page 64, for specifics on landscape-plant water needs). It is based on water losses from an evaporation pan. However,
for this method to be effective, you must make preliminary calibration of evaporation-pan results with actual turf wilting.Some moisture measurements involve either direct measure of soil moisture through oven drying and weighing
or indirect methods that measure the soil-moisture tension. The gravimetric method of determining soil-water content involves measuring soil’s weight loss after heating it in a warm oven for 24 hours. Follow this procedure
for determining weight by the gravimetric method:• Take a soil sample from the turf area at the onset of wilting and place it immediately in a sealed moisture-proof jar.• Weigh the moisture tin in which you’ll be placing the soil sample and record its weight.• Fill the moisture tin about three-quarters full of soil. Weigh it and record the weight.• Label the sample with a piece of paper.• Place the sample in a 220°F oven for 24 hours. • Remove from the oven, cool, remove the paper label and reweigh the dried sample. Record this weight. Subtract
the weight of the moisture tin from the actual wet Warm-season turfgrasses(Least to most water needed)BuffalograssCommon bermudagrassZoysiagrassSt. AugustinegrassCentipedegrassHybrid bermudagrassCool-season turfgrasses(Least to most water needed)Tall fescueFine fescuePerennial ryegrassKentucky bluegrassBentgrassTURFGRASS WATERREQUIREMENTS
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IRRIGATING ANNUALS, PERENNIALS AND BULBSBy mid-July, you know the price of your floral displays, especially if the maintenance crew has been hand-watering the beds because of an inadequate or non-existent irrigation system. All too often flower beds must rely on overspray from turf sprinklers or hand watering. Installing an irrigation system may be an attractive option.Many choices are available for irrigating bedding. Sprays, rotors, impacts, micro-sprays, microspinners and drip may all be good ways to water your plantings, depending on the situation. Let’s look at some of their specific applications.Some plants prefer to be washed and misted daily. Others do much better with little or no water on their leaves and blossoms. If you are considering a system that would provide over-the-top watering, be conscious of the possible disease problems associated with this type of irrigation (see section on diseases, Chapter 15).How much water to apply depends on many factors. Usually, you find out quickly if water is inadequate for summer annuals. Plants will not thrive and provide good color if they are under drought stress. Spring-blooming bulbs typically obtain enough moisture from rain and snow but, in unusually dry seasons, supplemental water may be necessary, even in the fall or early spring. Remember, just because the bulb has not yet sent leaves above ground does not mean it isn’t growing—it still needs moisture. Avoid overwatering your beds. Plants vary in their tolerance to soggy soils, but waterlogging is bound to bring problems. Unfortunately,
you cannot prevent excessive rainfall. All you can do in this case is maximize drainage and hope for drier weather.As a rule of thumb, flowers use about 25 percent less water than turf, depending on the varieties used and the mulch around the plants. This makes it appropriate to water flowers independently. However, it is often uneconomical to separately irrigate a small isolated flower bed from surrounding lawn or shrubs.Your judgment based on training and local knowledge will serve you in deciding what type of system to install. The best choice for one site might not be the appropriate method for another. Before making blanket recommendations, study each location’s needs. The key points to consider are: • Vandalism potential • Water cost • Water placement • Pressure and pressure variation • Initial cost • Maintenance cost • Durability of equipment • Longevity of system • Climatic conditions (especially wind) • Soil types • Slope.Armed with a site evaluation, you can identify potential systems that will work and price them to determine each system’s actual yearly cost. This will help make your final decision as objective as possible.# Rotors and impacts. There is a place for plastic rotors and plastic or brass impacts in large flower beds. These sprinklers water over the top of the canopy and should be on stationary risers or in pop-up canisters. Some rotors have 12-inch pop-ups available.# Sprays. Spray heads have been the most popular method of watering
flowers through the years. These sprinklers have watering arcs of 15 to 360 degrees. However, manufacturers also make specialty rectangular patterns for areas such as parking strips and medians.Plastic and brass spray heads are available in pop-up canisters that allow the nozzle to extend 2 to 12 inches above the body. You also can place them on factory risers or steel or PVC risers that add even more height.In case a riser gets tipped over, a flex connection should be located Advantages of rotors/impacts are:Disadvantages of rotors/impacts are:• Low application rates (good for tight soils or slopes)• Wind drift• Large coverage area with few heads (low initial cost)• High evaporation• Hard sprays can damage bedding• Plants get washed during every irrigation• Overspray onto sidewalks and roads• Heads are easy targets for vandalsAdvantages of spray heads are:Disadvantages of spray heads are:• Good application uniformity• High evaporation• Keep water within bed boundaries• Vandalism of heads• Relatively maintenance free• DurableAdvantages of micros are:Disadvantages of micros are:• Low initial cost• Easy to vandalize• Low application rates (good for slopes)• The requirement of special filters• Location flexibility• Wind drift• Low pressure required for operation• High evaporation• The ability to cover large areas with each circuit• High maintenance on heads• Plants get washed each irrigation
60 TURF & LANDSCAPE DIGEST # 2004 chapter 9and dry weights of the soil.• Calculate the percent of water content:weight loss after drying weight of oven-dried soil= % water content• After a thorough rain or irrigation on the area from which you took your first sample, wait a set period (12 hours if the area has sandy soil and 24 hours if the area has clay soil). Then take new samples of soil from this same area. Repeat Steps 1 through 7 with these new samples. They will indicate the water content at field capacity.• Calculate the irrigation point using the following formula:
Irrigate when the soil-moisture content reaches the irrigation point. IRRIGATION TIMINGYou can irrigate your landscape at any time during the day. However, the ideal time is in the early hours of the day. At this time, wind is minimal, and you reduce water
losses. Also, irrigating at this time gives water a better
chance to infiltrate into the soil before it is lost to evaporation.Watering at night or in the evening is a second choice to morning irrigation. Water loss to evaporation can be minimized at this time, but the moisture remaining on plant leaves overnight creates a condition conducive to disease development. Nevertheless, in some cases, such as on golf courses, night irrigation may be the only way in which you can practically water turf or a landscape without interrupting its use. Night irrigation is especially
practical with automatic irrigation systems.Daytime is the least preferable time to irrigate. Evaporative
losses are high, and wind also may be greater underground to prevent it from breaking. Specialty flex risers also are available. # Microsprays and spinners. Microsprays and microspinners are low-cost options to sprays. You can get nozzles attached to individual pop-up canisters, placed in shrub adapters on risers or inserted in special risers with a small poly pipe attachment holding the micros.Special risers that attach to poly pipe allow you to string poly pipe or drip tubing through the center of the bed. You can tee off of it with 1/4-inch poly tubing by using a barb adapter to run to each microhead location.Most micros have a relatively flat watering pattern, which requires you to place them above the canopy in most situations. However, on tall plantings you might be able to use them under the canopy.Even though running drip tubing with poly laterals to the individual heads is inexpensive and flexible, it only takes one big dog running through the bed to create havoc with whole system. The micro circuits also may require pressure regulation to 30 psi if static pressure
is high at the delivery point. You could use pressure-regulating micros, remembering that the drip-tubing system is designed to run at no more than 50 psi.# Drip emitters. Drip emitters are a low-gallonage option with water point-applied to each plant or row of plants. The emitter exit points are critical to the operation of the system because there is no surface spreading of water. Sandy soils require narrow spacing (possibly as close as 6 inches) while clay soils allow liberal spacing (perhaps every 2 to 3 feet). If you have flowers that demand more or less water, emitter spacing and sizing can match that demand.Low pressures of 15 to 30 psi tend to work best over a range of emitter types. The trick is to keep the pressure as constant as possible
throughout each circuit. This will give uniform emission at each outlet. If pressure constancy is a problem, use pressure-compensating
emitters. They cost more but they simplify your installations. Include a pressure regulator and filter (100 to 200 mesh) upstream of a drip circuit.Drip tubing is used as the water carrier through the system. It can be left aboveground, placed under mulch or buried 2 to 3 inches below the surface. To reduce vandalism, place tubing under the mulch or ground. This will require bringing 1/2-inch poly tubing to the surface from each emitter, if you want to observe its operation. Observation is the only way (other than wilted plants) you have of knowing each emitter is working.As stated earlier, the type of irrigation you use in your beds depends on numerous factors. As you can see, several effective options exist. In spite of the advantages of irrigation systems, hand watering still is widely practiced. The choice between hand watering and installing a system depends as much on available resources as it does on which is more effective. Both can produce satisfactory results, but installing a system is without question more labor-efficient.
Remote sites or those with no water access may require watering from tanks. Advantages of drip are:Disadvantages of drip are:• Precision watering• Easy to vandalize• No wind drift• Plugging of emitters• Operation does not interfere with any activies• High maintenance (filter cleaning, monitoring of emitters)• Less weed growth• Relatively short system life• Minimum evaporation• No plant washing• Low initial expense• Sandy soils require many emitters.• Flexibility in placement•Installer needs knowledge of plant material for proper emitter placement• Low-pressure operation• Potential water savings(Percent water content at field capacity+percent water content at wilting point)÷ 2x 100
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during the day. Turf temperature normally reaches a peak at 2 p.m. A light application of water (syringing) at this time will lower turf temperature and prevent wilting. However, keep in mind that syringing is not intended to provide water to turf roots. Instead, it is simply meant to cool turf by evaporating water.IRRIGATION RATEThe rate of irrigation always should be lower than the rate of infiltration. Allowing irrigation rate to exceed the infiltration rate results in water runoff. Slope also can influence runoff, because a steep slope encourages runoff.
In addition, soil factors such as texture, structure and, perhaps, thatch influence infiltration rate.Many tools are available to help you specifically determine
your irrigation rate. They include soil-moisture monitors, weather stations and using ET with turfgrass coefficients. Consider each:# Moisture sensors. These can provide the following benefits:• Reduce water use• Save money because of lower water use• Reduce leaching fertilizers past the root zone• Reduce runoff• Minimize damage to pavement, sidewalks and buildings
• Reduce client/customer complaints of over-watering while it’s raining• Decrease drainage problems• Provide lower maintenance expenses.Many different types of soil-moisture sensors are used in landscaping. The most common are tensiometers, solid-state tensiometers, electrical-resistance blocks and point-contact blocks. Tensiometers measure the matrix potential
or capillary tension in the soil. This is similar to the force a root must exert to take water from the soil.Electrical-resistance blocks measure the matrix potential indirectly. They consist of electrodes that are embedded in gypsum or plastics. As moisture content increases between the electrodes, electrical resistance decreases. You can calibrate electrical-resistance measurements to matrix potential for the soil in question. Point-contact blocks have many electrodes that measure moisture contact at each point.You can control residential and small commercial sites with one or two simple sensors or one sensor at each automatic-control valve. You should be able to adjust these sensors at the control valve or the automatic controller.
Large commercial sites, such as parks and highways, require more sophisticated sensor systems. These systems should meet the following criteria:• Sensors are adjustable from the automatic-controller location• The system provides manual or automatic sensor override• The system should need little sensor maintenance• Equipment can withstand freezing soils (if required)• Sensors are corrosion resistant.
Today, you can use soil-moisture sensors with several central/satellite control systems.
It is even possible to add some sensors to your existing irrigation system with little Figure 1. This illustration shows the proper installation for a moisture sensor. Locate it between heads that are operated by the same control valve.Sprinkler headRow spacing1/2 row spacingSprinkler spacing1/2 sprinkler spacing1/2 sprinkler spacing1/2 row spacingInstall 4 inches below gradeMoisture sensorSprinkler headsSensor wireValve boxSafe location for weather station is anywhere outside the disturbed air “box”Prevailing windDisturbed wind area2XObstructionX6X2XWeather stationFigure 2. Obstructions can affect a weather station’s instrument readings. The “X” dimensions here define the “box” of disturbed air that surrounds an obstruction (note the prevailing wind). You would not want to locate a weather station within this area of disturbed air.
62 TURF & LANDSCAPE DIGEST # 2004 chapter 9
additional wiring. (See Figure 1, above left, for information
on installing a moisture sensor.)# Weather stations. A weather station can provide you with the climatic parameters you need to calculate ET. The most common ET-rate equations in landscape irrigation
are Penman and Penman-Monteith. Both of these equations originally were calibrated for clipped grasses. They are based on 1-day’s data. Because turf’s root zone is so shallow—and hold-over moisture insignificant—1 day is a critical time element.Nevertheless, keep in mind that the following factors all can affect whatever equation you use:• The area’s historical climatic data• The time for which you need ET rates• Your location• Your plant type and its condition.Specifically, when using the Penman equation, you must have climatic information on:• Maximum and minimum temperatures (°Celsius)• Relative humidity (percentage)• Wind movement (kilometers per hour)• Net radiation (calories per square inch).To get this information, you must have a data logger. This equipment—basically a programmable computer—is located on the pedestal of the weather station. It queries sensors, storing the data for later retrieval. These sensors include:• Anemometer to measure wind speed• Tipping-bucket rain gauge to measure rainfall• Pyranometer, which monitors solar radiation• Temperature probe, which tests for maximum and minimum temperatures• RH probe, for relative humidity.Other factors you may find useful to monitor include:• Soil temperature• Wind direction• Soil moisture• Water quality• Pump pressure• Pump flow• Pump power.You can provide power for your station from a 110-volt AC source. Or you can use solar power or a 12-volt DC wet-cell battery.Locate your weather station away from obstructions, such as buildings or trees. Primarily, don’t let the irrigation
system throw water on it, and don’t shade it from the sun or shield it from the wind (see Figure 2, page 57).# ET and turfgrass coefficients. As mentioned previously,
by monitoring transpired water and water evaporated
from soil, you have a fairly good indicator of how much water turf uses each day: ET. Several tools are available
to help you monitor turf’s water use: atmometers and empirical models.# Atmometers. An atmometer is any tool used to measure the evaporating capacity of air. The most well-known example of an atmometer is the evaporation pan. Daily measurements of evaporation from the pan are converted
to turf ET with a crop coefficient, or multiplier: pan evaporation x crop coefficient = turf ET. Traditionally,
the evaporation-pan crop coefficient for cool-season grasses is about 0.80, while that for warm-season grasses
is 0.60. In other words, if 1 inch of water evaporates from a pan, you should irrigate a cool-season turf with 0.80 inch of water and a warm-season turf with 0.60 inch of water.# Empirical models. These models are equations that incorporate
climatic data, such as temperature, solar radiation, wind speed, etc., to generate a predicted ET value. Examples
of some commonly used equations are the Penman,
Penman-Monteith and Jensen-Haise. Modern irrigation
systems typically use a weather station and accompanying
software that allow the operator to estimate ET using an empirical model.IRRIGATION-SYSTEM COMPONENTSIrrigation systems are meant to uniformly distribute water to an area at a rate that does not exceed the infiltration
rate of the soil. An irrigation system is comprised of sprinkler heads, pipes, valves and a pump or city water source. When designing an irrigation system, you should give consideration to the compatibility of all components. Pipe size and length, valve size, and the size and number of sprinklers comprising an irrigation system must be Application ratePressure too lowProper design pressurePressure too highDistance from irrigation headFigure 3. If your operating pressures are too low, you get “donut”-shaped coverage. If you operate systems at pressures that are too high, you get reduced coverage.
2004 # TURF & LANDSCAPE DIGEST 63
compatible with the pumping system. All components of the system are meant to operate at specified flow rates and pressure, and their use beyond pressure and flow limits will result in unsatisfactory performance.Irrigation systems vary in complexity and cost. Homeowners
use simpler systems. They include flexible hoses with movable sprinkler heads, which may be supplied
with water from a municipal source. More complex systems include fixed irrigation systems, which may be completely automated. Aside from initial cost, in planning
an irrigation system, you should consider practical management of the system to supply water when it is needed. Turf managed under high intensity requires a significant amount of manpower to meet turfgrass requirements
if you use a manual irrigation system, whereas automatic irrigation systems can save considerable
manpower for other tasks.SPRINKLER HEADSThree major sprinkler-head types are used for turf irrigation:
oscillating, rotary and spray.# Oscillating or wave-type sprinklers. Residential customers are the primary users of these types. They are best suited to relatively small areas. Water is delivered through holes in an oscillating arm. Water delivery rate is slow with these types of sprinklers, and they are readily affected by wind.# Rotary or impact-driven sprinklers. These are the most widely
used heads on professional turf because they are best-suited for large turf areas. Coverages range from 40 to 200 feet in diameter. Rotary sprinklers deliver water in one or more streams and rotate by means of hydraulically
driven gears or by impact. Impact-driven sprinklers rely on the power of the water stream to impact a spring-loaded arm and move the sprinkler head. Repeated impact drives the spring-loaded arm and moves the head in an entire circle. Part-circle impact heads are also available, as well as adjustable heads. Rotary sprinkler heads deliver
the greatest amount of water nearest the water source, and the amount of water delivered diminishes as the application approaches its periphery. When you position heads properly to provide sufficient overlap, you can achieve relatively uniform coverage. Wind, however, will distort the pattern of rotary sprinkler heads especially
with heads covering a large area. The larger the water stream’s coverage area, the more susceptible the stream is to wind. Nevertheless, rotary sprinklers are the most economical and most efficient on large areas.# Spray-type sprinkler heads. Also referred to as fixed heads, landscapers use these most frequently on relatively small turf areas. The area of coverage is between 16 and 24 feet for a single head. You’d typically space heads 10 to 24 feet apart to provide overlap and uniform coverage. In contrast to rotary sprinklers, spray heads discharge water in all directions at once. The nozzle orifice of this type of sprinkler head is designed to provide a predetermined radius of coverage and flow at a specified pressure.Adjustable and part-circle fixed heads also are available. Spray-type heads are least affected by wind. These heads also apply water at a rapid rate and may not be suitable on heavily compacted soils. In addition, the area covered by individual spray heads is relatively small, thus necessitating
more sprinkler heads to cover an area in comparison
to rotary sprinklers.SPRINKLER-HEAD SPACINGFrom the previous discussion about sprinkler-head characteristics, it is evident that sprinkler heads differ in distribution pattern, area of coverage and response to wind. The ultimate goal in designing a sprinkler system is to achieve uniform water distribution. Because the amount of water applied per unit area decreases with distance from the sprinkler head, it is important to overlap
coverage among adjacent sprinklers. Wind also may influence the spray pattern, and you must take it into consideration when determining spacing.Spacing is generally referred to in terms of a percentage
of the wetted area. Distance between sprinklersPercent spacing = x 100 Wetted diameter of sprinklersPercent overlap = 100 - percent spacingFor example: 70 percent spacing = 30 percent overlap of spray patterns. 42 ft70 percent spacing = x 100 60 ft30 percent overlap = 100 - 70You can use several different approaches
to spacing in designing an irrigation
system for uniform coverage. Irrigating
with a multiple-row system is more preferable than with a single row of heads, because distribution is more uniform. Multiple-row system designs include square-spaced and triangular-spaced heads. Generally, square-spaced heads should have 50-percent spacing, and triangular-spaced heads should have 60- to 70-percent spacing.PRESSURE AND DISTRIBUTION PATTERNSCorrect irrigation-head placement starts by understanding
the available operating pressure at the site and 42’spacing60’coverageOverlap30%
64 TURF & LANDSCAPE DIGEST # 2004 chapter 9 DETERMINING LANDSCAPE-IRRIGATION REQUIREMENTSA cactus requires less water than a willow tree. Most people would agree with that statement. But what about the comparative water needs of other landscape plants, such as roses, citrus trees, oaks, azaleas or ivy?Recurring droughts in different parts of the United States during the past three decades have made it imperative that homeowners and landscapers know the answer to this question. Because of droughts, city water departments have put landscapes in many parts of the country
on a water budget. Landscape managers must design, install and maintain their sites to stay within these budgets, which are determined by a property’s size and local climate conditions. To meet these water budgets, you must know—among other things—the relative amount of water one species of plant uses compared to another.Even in times and in regions where the water supply is not critical, this information helps landscapers properly irrigate a landscape. To keep water costs down and to keep plants happy and healthy, group plants with similar water needs and irrigate them accordingly.How do you determine a landscape plant’s water use? Using landscape
coefficients is one way. Landscape coefficients are similar to crop coefficients. But, rather than estimating water loss through evapotranspiration (ET), as with crop coefficients, they help determine the amount of water needed to maintain a certain level or quality in a landscape. They take into account the fact that landscapes contain a variety of plants and microclimates and that the density of planting varies considerably too.The formula is:KL = Ks x Kd x KmcKL is the landscape coefficient.Ks is the species factor.Kd is the density factory.Kmc is the microclimate factor.In the table, “Species factor (Ks),” “Density factors (Kd)” and “Microclimate
factors (Kmc),” you’ll find the range of values for each factor.As an example, say you had a bed containing drought-tolerant ground cover and shrubs, such as junipers and manzanitas. The bed is well-established and shaded by a building in the afternoon. For this bed, Ks = 0.2, Kd = 1.0 and Kmc = 0.5. So KL is 0.2 x 1.0 x 0.5 = 0.10. In another bed, you have hypericum ground cover, a moderate water-user, growing on a slope in full sun but no wind. Here, Ks = 0.5, Kd = 1.0, Kmc = 1.0, and KL is 0.5.Once you know the landscape coefficient, you can multiply it by reference
ET to determine the amount of water the landscape requires each week. Depending on your state, values for reference ET are available from farm advisers, cooperative-extension agents and universities. Or irrigation-scheduling software often includes them. Knowing the landscape coefficient also will help when estimating water budgets for new projects.SPECIES FACTOR (KS)*Vegetation typeHighAverageLowTrees0.90.50.2Shrubs0.70.50.2Ground covers0.70.50.2Mixed plantings0.90.50.2*Species factor values for trees are based on research in orchards. Ground cover estimates are based on preliminary research. Because shrubs are similar to ground covers, species
factors for them are an approximation of ground cover figures. Mixed plantings include two or more vegetation types, such as trees, ground covers and shrubs.DENSITY FACTORS (Kd)*Vegetation typeHighAverageLowTrees1.310.5Shrubs1.110.5Ground covers1.110.5Mixed plantings1.310.6* Generally, the more leaf surfaces in the area, the greater the area's ET. For trees, density is a function of canopy cover or the percentage of ground under the tree shaded by the canopy. Sixty to 100 percent cover is average. For ground covers and shrubs, average density completely or nearly completely covers the soil. Mixed plantings have the highest densities of all and, thus, the highest potential for water use. If an area had a lot of bare soil, increase Kd to account for soil-surface evaporation.MICROCLIMATE FACTORS (Kmc)*Vegetation typeHighAverageLowTrees1.410.5Shrubs1.310.5Ground covers1.210.5Mixed plantings1.410.5*In average conditions, the equation assumes buildings, structures, pavement, slopes or reflective surfaces do not influence microclimate. If your site has features that increase evaporation, use the "high" Kmc column. These features include wind (wind tunnels between buildings), heat-absorbing
surfaces (parking lots), reflective surfaces (windows), etc. If your site has a lot of shaded areas or areas protected from wind, such as in courtyards or under building overhangs, use the log Kmc Column.
2004 # TURF & LANDSCAPE DIGEST 65
understanding irrigation-distribution patterns. Manufacturers
design irrigation heads to work within certain pressure ranges. Incorrect pressure has a direct effect on how evenly and how far the irrigation system distributes
the water. A pressure variation of only 5 psi can change the coverage radius of an irrigation head by 1 to 2 feet. Therefore, it is critical to make sure the pressure at the irrigation head is what the designer intended it to be.What happens when you operate an irrigation head above the suggested pressure? You distort the distribution
pattern and cause excessive wind drift and overspray.
As mentioned, you also reduce the effective throw of that head (see Figure 3, page 58). Operating a head below the manufacturer’s pressure recommendations also distorts the pattern, leaving turf areas with donut-shaped dry spots. If necessary, you may need to adjust flow controls or install pressure-compensating devices to achieve the proper pressure.Another consideration is the irrigation-head’s distribution
pattern. Irrigation distribution patterns influence spacing patterns, wind effects and system uniformity. Manufacturers, however, do not create all heads equally
or with the same distribution pattern. You can produce
different distribution uniformities for the same system, in fact, simply by selecting a different head—even when manufacturers claim the same radius, gpm and precipitation rate for that head. When that happens, the head with low distribution uniformity does not spread water evenly. This results in your running the irrigation system longer to make up for weak areas in the coverage. This means more water, higher water bills and saturated spots in areas with the heaviest coverage. Therefore, it is always a good idea to select irrigation heads with the most appropriate distribution patterns for a given application and ones with high uniformities.
A good way to evaluate irrigation uniformity during the design phase is with a computer program called SPACE (Sprinkler Profile And Coverage Evaluation). This program uses densograms to model irrigation-head performance using data collected by the Center for Irrigation
Technology from single-leg or full-grid catchment-
pattern tests. The program produces irrigation profiles and densograms for single heads and allows you to check uniformities for various square or triangular
spacing patterns. A program called Hyper-SPACE allows you to evaluate almost any type of irrigation head layout even if the spacing is not uniform. (To obtain a copy of the SPACE or Hyper-SPACE software programs, contact the Center for Irrigation Technology, California State University, 5370 N. Chestnut Ave., Fresno, CA 93740-0018, 209/278-2066.)The rule of thumb in irrigation-head spacing is head-to-head spacing. You use this rule to account for wind effects during irrigation. Manufacturers’ recommended spacing typically starts at 60 or 65 percent of the irrigation
diameter. This drops to about 50 percent (head-to-head) for conditions where you might expect the wind to exceed 4 to 8 mph. For some irrigation-head types, you must modify this spacing higher or lower to achieve better distribution uniformities and avoid excessively wet or dry patches.An important consideration is that different heads operated under the same conditions produce different uniformities. Some manufacturers design irrigation nozzles that produce a higher degree of uniformity than others do. As the industry places more emphasis on water conservation, it will become more important to select irrigation heads that produce the highest degree of uniformity possible for a particular application. For now, try and find out as much as you can about the irrigation heads with which you work and what their individual strengths and weaknesses are.Once you select the correct irrigation head, you need to consider proper placement. Accurate field staking is the single biggest error in the design or installation of a new irrigation system. Yet, maintaining consistent spacing is the only way to maintain a high degree of uniformity. After all, spacing that varies by as little as 1 foot (less than 7 percent) on a 15-foot radius head will change the average precipitation rate between
heads by more than 20 percent (see Figure 4, left).INSTALLING A BASIC SYSTEMIf you’ve never installed an irrigation system, 15 feet14 feet16 feet1.82 inches/hour1.39 inches/hourFigure 4. A spacing change of 1 foot (less than 7 percent) will result in a change in precipitation rates of more than 20 percent.
66 TURF & LANDSCAPE DIGEST # 2004 chapter 9
don’t be unsettled by the myriad details involved. To install a system successfully and within budget does require
attention to specifics—from design to maintenance.
However, with the basic facts at hand, you’ll have a starting point from which you can ask more detailed questions. Obviously, the most basic question you first must ask is, “Where will the water come from?” Then you can move on to consider the more complicated aspects. These include system, design, pipe considerations, system
options, component selection and the as-built drawing’s importance.WATER SOURCE AND PRESSUREOne of the first aspects to consider when installing an irrigation system is the water source. It can be from a municipal water supply, a well or a pond. If a municipality provides the water, it is important to know the size of the water service and the pressure delivered to the site. Also you should check with the water purveyor for local codes or regulations.If tapping into a main line in the street, your local water utility can provide the information needed.Before ordering materials for the irrigation system, you should verify the actual water pressure to make sure it matches the rate the water company says it does.You can determine the pressure on a small line with a simple gauge that measures the static pressure at a particular point in the water supply line. On large projects,
it may be wise to do a flow test that tells you about gallons per minute and the drop in pressure over the landscape.If you are installing a system on a golf course, you probably will need to construct several water retention areas or ponds as your water source. The size of these ponds usually is determined by the course’s irrigation requirements during the months of highest water consumption,
as well as the time constraints of the site during those months. An example of time constraints might be just how long the system can be on without interfering with players on a golf course.If you are installing a system on a residential site, you’ll most likely tap into the homeowner’s water supply.
In most cases, doing so is fairly routine. You probably
won’t even need a pump to get the appropriate water pressure. But to be sure, you’ll want to determine the demand for water and the amount of water and pressure available. For example, if the area is hilly—even on a small residential site—you may need a pump to supplement pressure coming into the site to serve the upper areas requiring irrigation.PIPE CONSIDERATIONSBefore you can begin designing the system, you must take several factors into consideration. Think about types of plantings, sun exposure, slope, soil type, average
rainfall in the area and design of the landscape itself.
Then you can choose the type of pipe—a relatively easy task because few choices are available. Of the two main options, polyvinyl chloride (PVC) pipe is typically
preferred over polyethylene (poly) tubing because of its strength and durability, especially on pressurized lines.In warmer climates, such as California, installers use PVC for both main and lateral lines. In cooler climates where soil is subject to quick-freezing conditions, however,
PVC is used for main lines and poly for the lateral
ones, at least in residential and small commercial systems. The reason for this: Even though PVC is stronger,
it also is more rigid. Thus, it is less flexible than poly tubing and cracks more easily.Laying pipes down deep also can help avoid problems in cold weather. An irrigation consultant can give you specific guidelines on how deep to lay piping in your area of the country and which type of piping to use. Use drain valves to empty water from pipes as another means of avoiding freeze damage.Installing your piping is another main consideration. To install polyethylene pipe, you’ll probably want to use a vibratory plow, also called a line-puller or drop-cable plow. If using a different piping material—such as PVC—which might not be strong enough to withstand being pulled through the soil, or if the site is extra hilly, another type of trenching machine may be more appropriate.
If the soil on a site is particularly rocky, placing sand around the pipe can prevent rocks and other sharp objects from puncturing the pipe. This is usually not a problem for most installers however.SYSTEM OPTIONSOften, irrigation consultants recommend that landscape
contractors use a combination of drip irrigation and spray heads or rotors to get water to root systems. For example, on large turf areas, it usually is most cost effective to use large, gear-driven spray heads on 40-foot spacings. Then, on smaller turf areas, use pop-up spray heads. Ornamental beds are where drip-irrigation systems
are usually most effective. You also will want to use them in arid areas with water restrictions.For the very reason that drip-irrigation systems are not out in the open, they can present problems not encountered when using other irrigation systems. Too often, once landscape contractors have installed a system,
home owners or maintenance personnel forget
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TLDabout the systems. After all, if a sprinkler head acts up, the problem is obvious. If a drip irrigation system gets clogged or a valve breaks, however, you can’t readily see it. Thus people don’t discover problems until plants begin to die. However, as long as you properly maintain and regularly inspect these systems, you probably will avoid major problems.COMPONENT SELECTIONPicking the proper sprinklers, valves and controllers can be tricky. Many manufacturers offer irrigation components; not all of them are necessarily equal. One manufacturer may make good spray heads, but its valves or rotors may not be as good as another company’s and vice versa.How can you make comparisons? Increasing numbers of manufacturers now provide distribution curves for each sprinkler they offer. These distribution curves chart how systems behave according to varying factors. For example, according to a manufacturer’s distribution curve, a given sprinkler with a certain nozzle will provide
different coverage at 50 pounds of pressure than it will at 70 pounds.A client or owner may not notice differences in coverage
most of the time. You can be sure, however, that during a drought year when irrigation uniformity is crucial, a client or manager will notice brown spots where turf did not receive adequate irrigation. Poor irrigation system design also will show up during periods
of drought.Other system components you need to consider are valves, controllers and rain or moisture sensors:# Valve selection. Valves come in plastic or brass. Which one you choose will depend on your particular situation as well as the budget. If an owner requests you use metal valves, or for other reasons a system needs a longer-lasting valve, brass should be your choice. In other situations, plastic valves are used frequently because
they are less expensive. Plus, every year, manufacturers
improve the quality of these products.# Controllers. Though some electro-mechanical controllers
are still on the market today, most installers usually
purchase solid-state controllers. Electro-mechanical controllers are easier to operate and fix, but they do not offer the flexibility and sophistication of solid-state models. However, solid-state controllers can be difficult to program and require a thorough reading of the manual. In fact, most maintenance calls concerning improperly working solid-state controllers often result from homeowners tinkering with the controllers after the contractors have programmed them.Advantages to solid-state controllers include flexibility
in programming multiple starts. Multiple starts allow you to coordinate infiltration rates that more closely match soil conditions. Electro-mechanical controllers, however, typically have only one or two programs available, and you cannot cycle zones as easily on these units.# Rain/moisture sensors. With increasing concern about water conservation, rain or moisture sensors are a must. In fact, some communities require them. Rain sensors are important because they prevent irrigation systems from operating while it rains. They are simple to operate,
require little maintenance and typically cost less than $40. Moisture sensors do their job by determining the amount of moisture in the soil and running irrigation
systems accordingly.Though problems have plagued these sophisticated instruments in the past, newer solid-state models work quite well. Unfortunately, rain and moisture sensors are often the first component disconnected by a homeowner
or maintenance person who believes the sensor does not operate properly. You can avoid this by showing
homeowners or maintenance personnel how the system works.AS-BUILT DRAWINGSMake sure that an as-built drawing of your irrigation system is completed during installation. Thousands of irrigation systems throughout the country are completed
each year without any record of how they actually
were installed. This can make future maintenance difficult.Though you easily can find sprinkler heads as long as they operate, valves are more difficult to locate. This is especially true if they were not originally placed in valve boxes or if grass grows over a valve box. Other system components, such as quick-coupling valves, also may be difficult to locate without a reference.ASK QUESTIONSObviously, installing an irrigation system is more complicated than described here. If you are uncertain about some aspect, ask someone who knows. Irrigation-design consultants or component manufactures can answer questions about the design and installation of irrigation systems.
Many people erroneously think that plants draw their food from soil. In reality, plants manufacture their own food through photosynthesis in their green tissue.
Soil provides most of the raw materials—mineral nutrients—that plants use as components for the food they produce.Scientists currently recognize 17 elements as essential for plant growth and reproduction (see table, “Essential plant nutrients,” below). These elements are divided into macronutrients—those that constitute more than 1,000 parts per million (ppm) of plant tissue—and micronutrients—
those that account for less than 100 ppm of plant tissue. In the turf and ornamental industry, however, many people use different terminology and refer to N, P and K as the macronutrients or just macros. Ca, S and Mg are the secondary nutrients, and the remainder are the micronutrients, or micros.All essential elements are necessary to plants in some amount, so a deficiency of any one of them would theoretically produce symptoms. In practice, however, deficiencies of some of the essential elements—Mo, B, Cl and Ni—are virtually unknown because they are present in most soils and plants need very little of them. C, H and O account for more than 95 percent of the dry-tissue weight of plants, but plants obtain these elements from water and air, rather than from mineral soil. Thus, these elements are never limiting to plant growth. That leaves N, P, K and Fe as the nutrients that commonly become deficient, and Ca, S, Mn, Mg, Zn and Cu that occasionally
are deficient. Nutrients often become deficient due to conditions that prevent their uptake or use by plants rather than actually being absent from the soil.Nutrients also are classified as either mobile or immobile, depending on whether the plant can transfer the nutrient
from one tissue to another. Deficiencies of mobile nutrients tend to show up first in older tissue, especially leaves, because the plant will withdraw mobile nutrients from these areas to supply the needs of newer growth. Deficiencies of immobile nutrients show up first in new growth because immobile nutrients cannot be transferred within the plant. Thus, new growth suffers if external sources are inadequate. In practice, this knowledge can be quite useful for diagnosis of deficiency symptoms.You’ll notice in the following discussion that chlorosis—
yellowing of normally green tissue—is a symptom common to many deficiencies. Though some clues help you narrow the problem down, it often is necessary to conduct soil and foliar testing to determine the cause of a chlorosis (or other) problem. Both types of testing are sometimes necessary because some deficiencies are caused by an excess of some other nutrient. Thus, adequate
soil levels of a nutrient may not necessarily result in adequate tissue levels.Most landscapes do not experience significant deficiency
of nutrients other than N, P, K and Fe. Golf greens are more prone to deficiencies than other turf or ornamental sites due to their sand root zones, which do not retain nutrients well.PRIMARY NUTRIENTS• Nitrogen. Plants require N, a component of many necessary
compounds within plants, in relatively large quantities.
Notably, N is vital for the production of chlorophyll, the green pigment involved in photosynthesis. The two major forms of N that plants obtain from soils are nitrate (NO3-) and ammonium (NH4+). Most other forms of N must undergo transformation (via microbial activity) into these forms before plants can use the N.Deficiency symptoms include slow growth and chlorosis. Chlorosis occurs because N is a component of chlorophyll, the green photosynthetic pigment in leaves. Chlorophyll production slows or stops when N is ESSENTIAL PLANT NUTRIENTSNutrientSymbolMobility in plantsSource (form available to plants)*Frequency of deficiencyMacronutrientsCarbonC-CO2NeverHydrogenH-H2ONeverOxygenO-O2 and H2ONeverNitrogenNMobileNO3- and NH4+CommonPotassiumKMobileK+CommonPhosphorusPMobileH2PO2~ and HPO4=CommonCalicumCaImmobileCa2+OccasionalMagnesiumMgMobileMg2+OccasionalSulfurSImmobileSO4=RareMicronutrientsChlorineCl-Cl-NeverIronFeImmobileFe3+ and Fe2+CommonBoronBImmobileH3BO3RareManganeseMnImmobileMn2+OccasionalZincZnMobileZn2+OccasionalCopperCuImmobileCu+ and CU2+NeverMolybdenumMo-MoO4=RareNickelNi--Never*Bold type indicates the preferred form when more than one form is usable.
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inadequate, resulting in yellow coloration. Leaves turn tan and then die in more severe cases. N is a mobile nutrient, so symptoms show up on older leaves first.Excess N promotes lush foliar growth, often at the expense of flowering, and creates a high shoot:root ratio.
This often increases drought susceptibility and may delay dormancy in fall, increasing the chance for frost damage.Plants perform best with consistent supplies of N. Slow-release fertilizers have become popular for this reason.• Phosphorus. After N, P is the most frequently deficient nutrient. Like N, P is a component of many necessary compounds within the plant, such as DNA, RNA and energy-rich ATP that drives the synthesis and decomposition
of organic compounds. Available forms include the phosphate ions H2PO4- and HPO42-. Soil pH controls which form is present—the latter predominates in pHs above 7.0, the former in pHs below 7.0. P-deficient plants are stunted and become darker colored, sometimes almost black. P is mobile in the plant, so deficiency symptoms show first in older leaves. Excess P promotes additional root growth, which decreases the shoot:root ratio—the opposite effect of N.Although P traditionally has been promoted as a root-growth enhancer, this benefit is usually overstated where established turf and ornamentals are concerned. However,
P does seem to speed establishment of seedlings, sod and herbaceous transplants. This is reflected in the high P content of so-called starter fertilizers.• Potassium. This nutrient is the third most commonly deficient element. It, too, is mobile in the plant, which uses K in the form of the positive ion K+. K is abundant in plant tissue. It plays a role in the osmotic potential of cells and therefore helps regulate turgor pressure. K also is important as an activator for many enzymes involved in photosynthesis, respiration, and protein and starch synthesis.In most plants, K deficiency produces slight chlorosis followed by necrotic (dead) lesions. Often, leaf tips and margins are the first parts to die, giving a scorched appearance
to the plant. Growth in general is stunted, as well. Excess K can cause deficiency of other nutrients such as Ca and Mg.SECONDARY NUTRIENTS• Magnesium. Mg deficiency first appears as interveinal chlorosis (IVC)—yellowing between the leaf veins. Available
to plants as Mg2+, deficiency is normally restricted to acidic soils with low cation-exchange capacity (CEC). Other deficiencies can cause IVC but only in neutral to alkaline soils, so a simple pH test often can narrow the problem down to Mg. Mg is mobile.• Calcium. Ca deficiency, as with Mg, is mostly seen in plants growing in low-pH, low-CEC soils. Ca2+ is the form plants use, and it is immobile in the plant. Calcium plays a role in cell-wall formation as well as cell-division processes. Thus, deficiency often results in twisted or deformed tissues and death in shoot and root tips. Excess Ca can result in a deficiency of Mg or K.• Sulfur. This element is rarely deficient. However, peculiar
soil conditions in a few regions result in inadequate levels. Available to plants as SO42-, deficiency symptoms result in a general chlorosis difficult to distinguish from N deficiency without laboratory analysis. Excess N may cause S deficiency in leaf tissue of trees. S present as an environmental pollutant in rainfall is a significant source of S in many parts of the country.MICRONUTRIENTS• Iron. Fe is commonly deficient in turf and ornamentals and—after N, P and K—this element is the most frequent supplemental nutrient that grounds-care professionals apply. Fe is usually present in soil in fair amounts, and deficiencies often result from soil conditions—especially high pH—that restrict Fe uptake by the plant. Fe deficiency produces pronounced IVC, though this will often spread to the veins as well. Fe is immobile in the plant, so symptoms first occur on younger growth. • Manganese. Mn is not required in great amounts by plants, and deficiencies—which are not common—are most likely to occur in alkaline soils. The symptoms include IVC and, in severe cases, necrotic margins and spots. Mn is available to plants as Mn2+ and is immobile in plants.• Zinc. Zn deficiency is rare in turf but occurs occasionally
in ornamentals, where it causes IVC and rosette formation. Excessive Zn can reduce Fe levels.• Boron, chlorine, copper, molybdenum and nickel are rarely or never deficient. If you ever experience a problem
with any of these elements, it usually stems from excessive levels, not deficiencies. B and Cl toxicities are not uncommon in some regions, and Cu can reduce Fe SYNTHETIC N SOURCESMaterialFormulaAnalysisRelease rateAmmonium nitrateNH4NO333-0-0RapidAmmonium sulfate(NH4)2SO421-0-0RapidCalcium nitrateCa(NO3)215.5-0-0RapidDiammonium phosphate(NH4)2HPO420-50-0RapidMonammonium phosphateNH4H2PO41-48-0RapidPotassium nitrateKNO313-0-44RapidUreaCO(NH2)246-0-0RapidTriazoneCO(NH)3(CH2)241-0-0SlowUrea formaldehydeVariable38-0-0SlowMethylene ureaVariable40-0-0SlowIBDU[CO(NH2)2]2C4H831-0-0Slow
70 TURF & LANDSCAPE DIGEST # 2004 chapter 10levels in plants if present in high amounts.Several of the micronutrients are available in chelate form. Chelates are much more available to plants than non-chelated forms and are the type you should use, when available, if you need to apply these nutrients.FERTILIZER NOMENCLATUREFertilizer labels list the fertilizer’s analysis, a three-part designation, such as 20-10-10, representing the percent content (by weight) of N, P and K respectively. Fertilizers
that contain these three nutrients are known as complete. Products that contain equal amounts of each are balanced, such as 10-10-10 fertilizer. These three nutrients, because of their importance to plants and their frequent deficiency, are the primary components of commercial fertilizers. However, manufacturers often add other nutrients, as well.Labels usually state how much N is soluble and how much is insoluble, indicating how much is rapidly available
and slowly available, respectively.P content is expressed on fertilizer labels as if it were in the form of P2O5, even though no such compound exists in fertilizers. This is an old convention that the industry has not bothered to change. Because P2O5 is heavier than elemental P, you must multiply the stated content by 0.44 to get the actual content in terms of elemental P. For example, a reported P2O5 content of 20 percent equates to around 9 percent actual P content.K is expressed similarly—in terms of K2O equivalent—and requires you to multiply by 0.83 to obtain the actual amount of elemental K present in fertilizer.SOIL CHARACTERISTICS AND NUTRIENT AVAILABILITYObviously, if a nutrient is not present in soil, the plant will suffer. Commonly though, as we’ve pointed out, the problem is not actual absence of the nutrient. Rather, soil conditions directly or indirectly prevent plants from utilizing it. The cation nutrients Mg and Ca are two notable examples
that become less available in low-pH soils. Conversely,
Fe is less available in many alkaline soils. Sandy soils—putting-green root zones being the extreme—with low CEC values hold fewer nutrients than heavier soils and soils rich in organic matter. Clay and organic matter have excellent abilities to hold nutrients in soil, especially those nutrients that form positive ions, including Ca, Mg and ammonium.If you have soil conditions that cause nutritional problems,
long-term solutions rest with soil modification. In the short-term, you easily can solve most deficiencies with supplemental fertility of the type needed. Chapter 2 discusses soil conditions and amendments in more detail.One important
factor affecting soil fertility is the carbon-to-nitrogen ratio (C:N) of organic amendments.
Organic materials high in carbon—especially
the activity of microorganisms for decomposition. These microbes use N as they act on the organic matter and may withdraw so much from the soil that inadequate amounts remain for plant uptake. This effect is temporary because the N eventually is released as decomposition progresses. In the meantime, which may last a year or two, N deficiency may exist. You must add supplemental N, up to 1 pound per 1,000 square feet for some materials, to counter this effect and to speed up the decomposition of the organic matter in the soil. C:N ratios below 50:1 contain enough N to avoid most problems. Higher values may indicate the need for supplemental N. Wood products such as sawdust may have C:Ns in the range of 400:1 to 500:1 and can tie up large amounts of N. You should have some idea of the C:N of amendments you use in your soil (see table, Chapter 2, for some examples).Another factor you need to consider, especially for woody ornamentals, is soil mobility of nutrients. Some nutrients are mobile within the soil profile. Others are not. Soil pH also affects soil mobility of nutrients. The practical implication of this is that you must place immobile
nutrients directly into the root zone (see “Fertilizing trees and shrubs,” page 78). This is in contrast to soluble nutrients, which you can apply to the surface and water into the root zone. This does not apply so much to turf because turf roots grow so near the surface that surface applications are generally adequate.FE R T I L I Z E R P R O D U C T SLet’s look at some of the types of fertilizer we apply to turf and ornamentals. Quick-release N fertilizers provide N in several forms (see table, “Synthetic N sources,” page 69). These products are the traditional fertilizers and dissolve readily in water. Therefore, they enter the soil solution rapidly and are almost immediately available to plants. They also are quickly depleted.Slowly available sources are not as immediately available
to plants but release N over a longer period and at more consistent rates, which is advantageous for several reasons.P fertilizers are in the form of superphosphate or treble SECONDARY AND MINOR NUTRIENTSElementPrimary forms in fertilizersCalciumGypsum, dolomiteMagnesiumMagnesium sulfate, dolomiteIronIron sulfate, Fe++*ManganeseMagnesium sulfate, Mn++*ZincZinc sulfate, Zn++*CopperCopper sulfate, Cu++*BoronBoraxMolybdeumSodium molybdateChlorinePotassium chloride*These nutrients are available in chelated forms that keep them available to plants longer. Chelating agents include EDTA, DTPA and EDDHA.
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superphosphate. However, ammonium phosphates also provide P. K fertilizer is derived mainly from potash—KCl. Potassium sulfate and potassium nitrate are also important sources of K.The secondary and micronutrients are available in forms you can apply separately (see table, “Secondary and minor nutrients,” opposite page) if the need arises. However, special mixes that contain many of the secondary
and micronutrients are available, and turf managers often use this “shotgun” approach to ensure that micronutrient
deficiency is not a problem.Various combinations of fertilizer materials can provide
an endless array of analyses (see “Example fertilizer
label,” right), and manufacturers provide fertilizers blended specifically for almost every type of turf or ornamental in a given climate. Custom blending often is available, too.Turf and ornamental fertilizer products typically contain
N, P, and K and often Fe, as well. However, they may also include many of the other nutrients, too. This usually causes no harm, though the need for these nutrients in many situations is questionable.• Salinity. Some fertilizers are salty—they will increase the salinity of your soil. This may or may not be a problem depending on a variety of factors, but you should be aware of the salinity of the fertilizer materials you are adding to your soil, especially if your soils are already prone to salt buildup (see table, “Salt index,” at right).• Acidifying effects. Some fertilizers increase acidity more than others, and some have the opposite effect. You can use this as a means to alter (or maintain) pH levels by choosing a fertilizer with the desired quality (see table, “Acidifying effect,” at right).SLOW-RELEASE FERTILIZERSEvidence exists that N-deficiency symptoms result not from low N levels, per se, but from unsteady levels of N and cycling between high N and low N levels. This may be one reason for the effectiveness of slow-release fertilizers and their popularity. Their gradual nutrient release helps level out the peaks and valleys of turf growth, resulting in more consistent turf quality and fewer deficiency symptoms. Manufacturers produce two types of slow-release products: uncoated and coated. Coated products rely on semi-permeable or impermeable coatings to restrict water’s access to soluble fertilizers. Uncoated products take advantage of the low solubility of some N materials to slow their release. • Uncoated products. Ureaform (UF) and methylene urea (MU) are similar products that result from a reaction of urea with formaldehyde. Both contain about 40 percent N in the form of long chains of molecules. Longer chains are less soluble than shorter chains and so take longer to become available in soil. UF and MU both consist of a variety of chain lengths and so release N over time. UF molecules are generally longer than MU chains, so UF releases N more slowly but over a longer period. These fertilizers ideally release N over 8 to 12 weeks. However, because they rely on microorganisms to attack the molecule and mineralize the N, this release time can vary depending on conditions,
such as temperature, pH and soil moisture, that affect microbial activity. Thus, at certain times of the year, soil temperatures may be too low for UF and MU to supply adequate N to turf.Isobutylidene diurea (IBDU). The other significant uncoated
slow-release product available in the United States is IBDU. Formed by a reaction of urea with isobutraldehyde, it contains
32 percent N and is available in granular or SALT INDEX*Ammonium nitrate105Sodium nitrate100Urea75Potassium nitrate74Ammonium sulfate69Calcium nitrate53Ammonia47Diammonium phosphate34Monammonium phosphate30Treble superphosphate10Superphosphate8Gypsum8* Salt index is a relative measure of the salinity
of fertilizers. A high salt index indicates high potential to burn turf as well as increase soil salinity. Sodium nitrate is the benchmark value against which other materials are compared with a salt index of 100. Because manufactures vary their formulations, these values (for the basic product) may not match those of actual formulated products, whose salt indicated may be by acceptable.ACIDIFYING EFFECT*Ammonium sulfate110Diammonium phosphate75Urea71Ammonium nitrate62Monammonium phosphate58Potash0Superphosphate0Treble superphosphate0Potassium nitrate-23*Acidifying effect measures a fertilizer's ability to raise or lower pH. These values refer to the number of pounds of calcium carbonate
necessary to neutralize the acidity in 100 pounds of the fertilizer.EXAMPLE FERTILIZER LABELThe label below is from a fertilizer product containing IBDU and SCU. It provides a breakdown of N types present in the product, as well as the form of the materials used to provide the nutrients. Further, it provides useful information on potential acidity.SLOW-RELEASE FERTILIZER WITH IBDU/SCU32-3-8 Guaranteed analysisTotal nitrogen (N) ....................................................................32.0% 1.2% Ammoniacal nitrogen 3.6% Water-insoluble nitrogen 6.1% Coated slow-release urea nitrogen 21.1% Water-soluble nitrogenAvailable phosphoric acid (P2O5) ...........................................3.0%Soluble potash (K20) .................................................................8.0%Sulfur (S)...................................................................................... 7.0%Derived from ammoniated phosphates, urea, isobutylidene diurea,
sulfur-coated urea and sulfate of potash. Potential acidity is 1,200 pounds calcium carbonate equivalent.
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powder form.IBDU slowly releases N by hydrolysis in water, after which it is soon available to plants. IBDU acts as a slow-release product because of its low solubility—only small amounts dissolve and release over time. Moisture levels primarily affect IBDU release—dry conditions delay release. Superintendents also should be aware that powdered
forms they apply to greens dissolve more quickly than the granular forms they apply to fairways.LIQUID SLOW-RELEASE FERTILIZERSSome products have chemistry and release patterns similar to UF and MU but are liquid-applied. These provide
important advantages in certain situations. For example, liquid fertilizers allow you to tank-mix with pesticides, which is a great advantage in some operations.
Plus, it’s easy to customize the mix by altering the rate of each component you use in the mix, something not so simple to achieve with granular products. Gaining
these benefits without sacrificing the advantages of a slow-release product make liquid slow-release fertilizers attractive options in many situations.Another advantage of liquid application is more precise placement of the fertilizer than broadcast spreaders can achieve, making it efficient for areas such as golf greens and tees. Plus, liquids do not leave granular material on the green’s surface and so do not disrupt putting quality.COATED FERTILIZERS• Coated fertilizers. Since its introduction nearly 20 years ago, sulfur coated urea (SCU) has enjoyed great success in the turf market. SCU consists of a urea granule with a sealing coat of sulfur plus wax. Thus, SCU supplies turf with S in addition to N, which varies from 30 to 38 percent. Small cracks and imperfections in the coating layers allow some water to enter the granule and dissolve the urea, which then escapes out into the soil. Plus, microbes attack the wax coating and destroy it over time. Once a granule takes in water, it can release its urea quickly. Coatings
vary in thickness and integrity, so the gradual release of urea is a result of some granules releasing urea soon, some later and others only after a long period. Overall release rates vary among products and manufacturers, who can control the coating thicknesses. • Polymer-coated fertilizers date back to the introduction
of Osmocote in the 1960s. However, many of the polymer-coated products available now are relatively recent
introductions. Unlike SCU, many of these products contain other sources of N such as ammonium nitrate, as well as other nutrients such as P and K. Manufacturers are able to manipulate the chemistry of the coatings (wherein lies the main difference between various polymer-coated products) to provide highly predictable
release rates. They manufacture these products by applying successive polymer coatings to the fertilizer granule.When water diffuses across the semipermeable polymer
membrane, it dissolves some of the fertilizer inside. This creates a concentrated solution, which then diffuses back out into the soil. This continues over time until the fertilizer is completely released and all that remains is an empty polymer shell.OTHER FERTILIZER PRODUCTS• Natural organics. These products are derived from many different substances, such as composted sewage sludge, animal waste, feather meal and others. Nearly all of the N in these products is in organic form and relies on microbial activity for release. These products are considered slow-release fertilizers. Natural organics ClippingsKNO3(NH4)2SO4NO3#-#3#2NH4#3##UreaUrea#Organic#1+3#4Microorganisms##Soil organic N#5##46#45#5N2O, N2NH39##8Fertilizers#7 Conversions1 Urea hydrolysis2 Nitrification3 Plant uptake4 Microbial uptake (3+4 = immobilization)5 Decomposition6 Mineralization Losses7 Nitrate leaching8 Denitrification9 Volatilization#SomeorganicfertilizersFigure 1. The turfgrass N cycle. Arrows represent processes connecting the various pools of N. See inset for a listing of conversions and losses.
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typically have relatively low N content and, therefore, generally cost more to apply the same amount of N. However, N-use efficiency tends to be high.• Fertilizer/pesticide combinations. These products combine fertilizer with a pest-control product, often a herbicide or insecticide, for turf use. The economic advantages are obvious—fewer applications, fewer packages
to deal with and simpler, less expensive application equipment. Thus, when appropriate, these products may offer significant time and money savings. However, a significant drawback is timing. Obviously, the proper timing for the fertilizer and pesticide must coincide or one of them will have less than maximum effectiveness. Despite this disadvantage, combination products are a popular option with turf managers.FERTILIZING TURFTurf requires nutrient management significantly different
than ornamentals, so we’ll discuss turf fertilization separately. N is the most significant nutrient so we’ll start with this nutrient and then touch on the remainder.To understand turf’s N needs, it helps to understand the nitrogen cycle. The N cycle consists of numerous components
and processes, all interconnected and dependent on each other (see Figure 1, page 72). Let’s first discuss the components, or pools, of N in the cycle and then the processes that link them together.• Pools. N exists in many forms—all are either organic or inorganic. The forms of organic N with which most turf managers are familiar are products such as IBDU, urea, urea formaldehyde, methylene urea or composted sewage sludge. While these are important in turf-management programs, their application represents a small fraction of the total organic N in soil. The bulk of organic N in soil exists in the form of plant material (dead or alive), bacteria, fungi and other soil organisms. Humus also contains organic N. A fertile soil may contain 3,000 to 5,000 pounds of N per acre in the top 6 inches.By comparison, the inorganic N pool, consisting of nitrate and ammonium, is much smaller—in the range of 10 to 50 pounds per acre. Inorganic N is the critical link between soil organic N and turf growth because inorganic forms are the forms plants can use. N enters the inorganic pool either by fertilizer applications or microbial breakdown of soil organic matter into ammonium
by mineralization. Additions of fertilizer are predictable and easy to manage. However, the contribution
of mineralization to the inorganic pool is difficult to assess because it depends on the overall size of the organic-N pool, microorganism activity, temperature, pH and other factors.Further confounding the picture is the fact that the soil organic-N pool is not constant but expands over time, especially in a young turf site. For example, a new golf course built on heavily cultivated agricultural soil may initially have relatively low levels of soil organic N. After several years under turf, however, organic-N levels begin to increase due to fertilizer applications and recycled clippings that ultimately deposit their N in the organic pool. This pool will continue to increase in N content over several decades until it levels off.During the initial period of rapidly increasing organic N, the flow of N is primarily into the organic pool, with little N flowing back out into the soil. However once the pool is “full,” equal amounts of N flow into and out of the pool. This is important because the flow of N from a full pool back into the pool of inorganic N is significant
and can reduce the amount of N fertilizer the turf requires. Thus, a young, high-quality turf may require 6 to 8 pounds of N per 1,000 square feet annually, whereas a mature turf may succeed with 2 or 3 pounds annually. Also, the flow of N from the organic pool is fairly steady through the growing season and will support turf growth without the peaks and valleys associated with applications
of quickly available N fertilizers. Superintendents who have managed older courses are well aware of this phenomenon because it’s like having a huge supply of slow-release N “in the bank.”One of the best ways to increase your N pool is to return
clippings. Research has found that you can remove as much as 4 pounds of N per 1,000 square feet annually in clippings.• Processes. N pools in the soil are in constant flux, with flow from one pool to another. The links or paths between them are processes. We broadly group these into processes that conserve N in the system and those that result in permanent N loss from the system.• Nitrogen loss. The three basic processes that steal N from turf systems are volatilization, denitrification and leaching
(removal of clippings can be considered a fourth). Volatilization is the loss of N from the surface of the system into the atmosphere as ammonia gas (NH3). Depending on conditions, volatilization losses can range as high as 45 percent of the N you apply. Several factors increase this loss, including using ammonium-based or uncoated urea fertilizers, high soil pH, rapid drying conditions, urease activity and failure to irrigate after application. An irrigation of about 0.5 inch of water soon after application greatly reduces volatilization losses.Denitrification is the second process that steals N from turf. Denitrification also results in the loss of N as a gas. But instead of loss as NH3, N is lost as nitrous oxide (NO2) and nitrogen gas (N2). Microbial activity causes denitrification and can result in 10 to 90 percent of applied N being lost. Conditions that favor microbial activity, such as warm, saturated soil and high fertility, also increase denitrifica74
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seems to be fairly insignificant
soil, so maintaining
good drainage should reduce
this avenue of N loss.Leaching, the third avenue of N loss, is of great concern considering the potential harm of nitrates in drinking water. However, most research
indicates that healthy, dense turf loses little nitrate through leaching.• Nitrogen conservation. Several processes result in changes in the form of N without actual loss from the turf system. To illustrate, consider what happens when you apply urea to turf.A granule of urea dissolves fairly quickly following application, especially with irrigation. Several processes act on the urea, but the most important is hydrolysis by the enzyme urease, which converts N from the urea form into the ammonium form. Urease is present all through turf systems. It is produced by many living organisms but functions independently in the environment as well.The ammonium that urease releases can follow several
paths. As a cation, it can stick to cation-exchange sites, or soil microorganisms can convert it to nitrate through nitrification. In either case, the N is now available to turfgrass roots. Urea N is too but is used more slowly than ammonium or nitrate. Turfgrass roots can absorb 50 to 90 percent of applied N and can do so within 2 to 4 days. This is very efficient compared to most plants and demonstrates the value of healthy turf with extensive rooting. Rapid uptake fixes N in the system and prevents loss through other processes. A drawback of rapid uptake is that it causes cycling of N levels that results in inconsistent growth.Microbial absorption competes with plants for N and may account for 10 to 30 percent of applied N. Plant and microbial assimilation of N into living tissue is called immobilization. This is the opposite of mineralization. Living organic matter is just a temporary stopping point for N. When organisms die, they release their N back into the pool of soil organic N. Microorganisms convert fresh organic matter into humus through the complex process of decomposition. Microorganisms subsequently process the soil organic N back into NH4 by mineralization, completing
the cycle. Remember that all of these pools and processes are interconnected and interdependent. • Potassium and phosphorus. Turf’s response to P and K is not usually as visible as it is with N. However, these nutrients are just as necessary for good turf health and vigor. P is important to root growth and therefore affects establishment, both from seed and vegetatively. Deficiencies
slow establishment and reduce vigor by reducing root development. Severe deficiencies result in reddish purple leaf blades and poor growth. K is needed in large quantities by all plants. From a practical standpoint, improved stress tolerance is the most important function of K, so a visible response may not occur if the turf is not under stress at the time. However, adequate levels are vital for good tolerance to environmental
stresses and diseases. Visible deficiency symptoms include leaf-tip death and thin turf. Turf fertilizers usually contain enough P and K to prevent serious visible deficiencies. However, soil conditions—
especially low CEC—might cause low levels or reduced plant uptake to the point where vigor or stress tolerance is reduced. Therefore, soil and tissue analysis is warranted to ensure P and K levels are adequate. A lab with turf experience should perform these tests. Not only will the analyses detect deficiencies, they can tell you whether you are applying too much of these nutrients. Doing so is wasteful and could cause deficiencies of other elements such as Fe and Zn.• Iron. Fe is the micronutrient most likely to be deficient in turf. Its primary function in the plant is in the formation
of chlorophyll. Because of this, chlorosis is the main symptom of Fe deficiency. Fe chlorosis is common when soil pH is above 7.0, because alkaline conditions change Fe to a form unavailable to the plant. In low-pH soils, Fe deficiency is relatively uncommon.Soil tests often are unreliable in reporting Fe levels. The easiest and surest way to test your turf is to apply a dose of iron to a section of turf. Turf’s response to Fe is quite rapid, and you will see a response within 48 hours or less if Fe is deficient. Turf response to Fe often is short lived so periodic applications may be necessary where Fe-availability problems exist.• Magnesium. As already discussed, low-pH and low-CEC soil can cause Mg deficiency. This is common, therefore, on golf greens. Turf managers often mistake the chlorosis caused by Mg deficiency for Fe or N shortage. If turf does not green up after application of these two nutrients, suspect Mg deficiency. Test spray a small section of turf with Mg to confirm this. You’ll see a response in 24 hours NITROGEN NEEDS OF TURFGRASS SPECIESSpeciesN requirementBermudagrassHighLowKentucky bluegrassBentgrassesSt. AugustinegrassPerennial ryegrassesTall fescueZoysiagrassFine fescueCentipedegrassBahiagrassBuffalograss##
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if Mg has been lacking. Epsom salts is a widely available source of Mg you can use for this test. Use 1 teaspoon in 1 pint of water.• Calcium can become deficient in the same conditions that reduce Mg. However, in practice, low-pH soils usually
are limed long before they become Ca deficient. Because
Ca is the primary component of lime, Ca deficiency symptoms are rare in the field.• Manganese. Deficiencies are rare but may occur on golf greens. A simple test application of Mn-containing fertilizer next to a strip of turf fertilized without Mn will confirm any suspected deficiency. • Sulfur, as already stated, is adequate in nearly all soils and also is supplied by rainfall in many areas. Even so, many fertilizer products include S, making deficiency even less likely. Again, a small test application of elemental
S will confirm if S is deficient when you suspect a problem.The remaining nutrients are not generally deficient in turf. The rare situations where they are inadequate can be dealt with by applying one of the available micronutrient
solutions to turf. These products usually contain trace amounts of the micros and easily satisfy the needs of the turf.RATESIt is difficult to generalize about fertilizer rates on turf. Different species require different amounts of N (see table, “Nitrogen needs of turfgrass species,” page 74). Climate and other environmental factors also vary nutrient demand, and intensity of use and level of maintenance
are issues as well. Many turf sites, such as home lawns, can perform well with a range of fertilizer rates, depending on the level of quality the owners desire. Thus, no single formula exists for determining how much fertilizer
to apply, and no perfect fertility program exists for any turf. Fertility has many indirect effects, and the interaction
between nutrient levels and other factors is often subtle and complex. Peculiar and unexpected problems sometimes arise, and grounds managers may be forced to experiment to find their own solutions to fertility problems.
For example, some diseases become more prevalent with high N levels, while others react oppositely. Weed problems change with varying nutrient levels as well. Because so many factors are site specific, turf managers must find what works for their particular situation. Having
said that, let’s be more specific.Fertilizer rates usually are given in terms of pounds of N per 1,000 square feet. Thus, for example, when you hear “2 pounds of N,” it’s implied that this means 2 pounds of N per 1,000 square feet. That is the convention we’ll use here. Fertilizer products often have a nutrient ratio of 3:1:2 for N, P and K. This reflects the needs of turf for these nutrients. By keeping with the desired ratio, varying the level of N you apply also results in proportional variation of the other nutrients present in the formulation, keeping them properly balanced for turf’s needs.As a general rule, 1 pound of quickly available N should be the maximum you apply at any one time to turf. In hot summer conditions, reduce this maximum to 0.5 pound of N for cool-season turfgrasses. You can safely apply up to 3 pounds of slow-release N at once, but more than this is risky. Close-cut turf such as golf greens should receive no more than 0.5 pounds of N from a quick-release source in one application.Ideally, N levels should be kept as even as possible. This limits ups and downs in frequency of mowing and reduces deficiency symptoms between fertilization. That is why slow-release products are useful and, in the case of quick-release sources, why it is better to apply less fertilizer more often. However, this must be balanced against the cost of labor, which will be lower with less frequent (and presumably heavier) applications. Applying 1 pound of N at a time is a middle ground that seems to work for many turf managers. Here are some of the major turf uses and some typical N requirements for them. Keep in mind that these are only examples and that rates vary widely according to climate, species, turf use and maintenance intensity.A reasonable range for golf greens is 0.75 to 1.5 pounds of N every 2 to 6 weeks during the growing season. This is a large range, and the actual rate depends on climate, rainfall and length of growing season. For example, warm, rainy, tropical climates result in nutrient leaching,
rapid growth and a long (sometimes continuous) growing season. N demand in this type of situation could be close to 2 pounds of N per month all year long. You should base P and K (and other nutrient) applications on soil tests, but you can expect demand for these nutrients also to be high on golf greens. Temperate climates result in considerably less demand.Fairway rates vary according to region and species, but 2 to 3 pounds of N annually is a reasonable average
figure. The need will be higher in tropical climates, perhaps more than double. The objective is to apply the minimum necessary to maintain a dense, vigorous turf without creating undue mowing requirements. Depending on many factors, 2 to 6 pounds of N annually
are required by lawn turf. Low-N turf such as buffalograss may need no more than 1 pound each year to look its best.Athletic fields require up to 10 pounds of N annually depending on the level of play. However, if fertilizations result in succulent turf, you should adjust rates or timing: succulent turf is more tender and suffers more from traf76
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fic. Conversely, inadequate levels will prevent turf from recovering from damage.TIMINGOne obvious principle for timing fertilization is that nutrients must be present when turfgrasses are actively growing. For cool-season turfgrasses that is fall and spring, and summer for warm-season species. Conversely, you should withhold fertilizations when turf is dormant. This can be during summer drought or winter dormancy. Nutrients applied at these times will largely be lost by the time the turf becomes active again.• Cool-season turf. During late fall and early winter, air temperatures may be low enough that shoot growth is minimal or non-existent. However, soil may still be relatively warm and root growth continuing. Fertilization
during this time is beneficial because the plants are still photosynthesizing and producing food. However, because it’s too cold for shoot growth to occur, this food is either stored for use the following spring or used for root growth. Thus, fertilizing at this time increases winter
hardiness and promotes earlier greenup and spring vigor. If you could make just one application of fertilizer each year, this would be the time. Though N is the main reason for fall applications, K is known to increase low-temperature tolerance.Usually, you will apply more N than just a fall application.
Mid-spring is a typical time to apply additional fertility. This aids the turf during its spring growth push. However, increased N during the warm season increases disease susceptibility in cool-season species. Thus, although
you may wish to add additional fertilizer in late spring and summer to turf that is irrigated throughout the season, you must balance the need for nutrients with increased problems you may encounter. Any such applications
should be light.• Warm-season turf. If you had to make just one application to warm-season turf, it would be in late spring, just as turf is starting its annual push. Additional applications are helpful through the summer, as the growth of warm-season species is at its peak during summer months. However,
you should avoid late-season fertilizations because this will reduce winter hardiness.• High-use turf. High-use and close-cut turf require specialized
fertilization practices. Golf greens need more consistent and continuous nutrient supplies. Therefore, superintendents fertilize often with smaller nutrient doses. This so-called spoonfeeding takes place throughout the growing season. Athletic fields likewise benefit from numerous lighter applications. Because many sporting events take place during late fall, winter and early spring, it may be beneficial to fertilize earlier in the spring and later in the fall than you would ordinarily.CHOOSING PRODUCTSAs you can see, many factors affect turf needs, and your fertilizer choices should reflect those needs. For example, a product with a high acidity rating may be a better choice for alkaline soils. Low-CEC soils benefit from higher fertilizer levels of cation nutrients. Inclusion of many of the secondary or micronutrients should be based on visible symptoms or soil and tissue tests. Of course, price and availability of fertilizers matter as well. You can satisfy N needs with a variety of materials, so other factors may be more critical than N form.TURF-APPLICATION TECHNIQUESFertilizers are delivered to turf in two basic forms: liquid and granular. Both have relative advantages and drawbacks.• Liquid application results in the most rapid uptake of nutrients because of foliar absorption. When you use heavier amounts (3 to 5 gallons per 1,000 square feet) of water, this is referred to as liquid fertilization because much of the solution runs off into the soil where roots NUTRIENT-DEFICIENCY SYMPTOMS OF TREESElementDeficiency symptomCommentsNitrogenLeaves are light-green to pale-yellow and perhaps smaller than normal.Excess N may be more common than deficient N in woody plants.PhosphorusLeaves turn purple, reddish-brown or dark green (almost black). Thin crown.Excess P may show up as deficiency of S, Zn or Mn.PotassiumLeaf scorch on older leaves. Reduced shoot growth. On rosaceous
planes, leaves curl upward and develop necrotic spots.Excessive K my cause deficiency
of Ca or Mg.CalciumRoot tips turn brown and die. Leaves curl, turn brown and die. Newly expanding leaves my stick together and tear as they open.Excess Ca may cause Mg or K deficiency.MagnesiumInterveinal chlorosis (IVC).Symptoms occur in acidic soils.SulfurPale-green or yellow leaves.S-deficiency symptoms are identical to N-deficiency
symptoms. Use foliar analysis.IronIVC in new leaves, then on older leaves as deficiency worsens.Often blamed for Mn or Zn deficiencies. Occurs commonly
in alkaline soil.ManganeseIVC. In severe cases, leaves develop necrotic margins and spots. Leaves my be smaller and less distinctly shaped.Occurs more in alkaline soil.Zinc and copperIVC, stunted growth. On some rosaceous
plants, leaves may form rosettes at the ends of shoots.Excess Zn or Cu will reduce
iron levels in plant tissue.
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can take it up. Under about 0.5 gallons per 1,000 square feet, we call it liquid feeding. In this case, most of the liquid remains on the foliage, and a great proportion of the nutrients
are directly absorbed by the leaf blades. Use only low rates (under 0.125 pound of N) for liquid feeding to avoid burning.Although spray rigs can cover a large amount of turf efficiently, they cannot compare to large spreaders in coverage speed. However, they are an efficient method of spoonfeeding turf that many turf managers use with success. Further, liquid applications allow operators to tank-mix pesticides with the fertilizer, which is a great convenience.• Fertigation is the practice of applying fertilizers through an irrigation system. Fertigation is problematic without high irrigation uniformity, because varying levels of fertilization can become visible. Even so, this practice is becoming more popular because it reduces spray applications.
• Granular application is the most widely used method in most situations. Granular formulations are easy to handle,
and the equipment is simpler to clean and maintain. Further, many pesticide/fertilizer combination products are available for added efficiency.# Drop spreaders are highly accurate tools for placing fertilizer
exactly where you want it without material ending up in non-target areas. However, they cover turf rather slowly and may result in skips if the applicator is not careful. This problem is reduced by halving the application
rate and then making two passes at right angles to one another. # Broadcast spreaders are used by many turf applicators because of their speed of application. Placement of material
is not as precise as with drop spreaders, but their efficiency is high and that’s why they are the preferred type of spreader in most situations.One problem with broadcast spreaders is differential distribution of different materials in a granular mix. This happens because particles of different size and density travel different distances when the spreader throws them. For this reason, you should apply materials
of greatly different size or weight separately or with a drop spreader.Broadcast spreaders come in a range of sizes and capacities,
from tiny models suitable for homeowners to professional
models with large-capacity hoppers. Belly grinders are over-the-shoulder types that hang across your chest and have a hand-turned crank that throws the fertilizer. # Pendulum spreaders are suitable for large areas such as parks, fairways and athletic fields. They typically are tractor-mounted and PTO-driven, with large-capacity hoppers. They use a discharge spout or tube that swings back and forth to spread the material. Spreading widths DRILL-APPLICATION RATESTo calculate how much fertilizer to place in each drill hole, do the following:1. Use a 2-, 2.5- or 3-foot square-grid hole spacing. This amounts to 250, 160 and 110 holes per 1,000 square feet respectively.2. The next step is to determine the amount of fertilizer you need per 1,000 square feet. If you wish to apply the recommended 3 pounds of N per 1,000 square feet, use the fertilizer analysis formula to determine the total weight of fertilizer you’ll apply. For example, a 30-10-10 fertilizer is 30 percent N by weight. To apply 3 pounds of actual N with this analysis, you’d need 10 pounds of fertilizer. This is determined by the following formula:N rate (poundsper 1,000 square feet) pounds of fertilizer x 100 = per 1,000 square Percent N in feet the fertilizeror ([3 ÷ 30] x 100 = 10 pounds of fertilizer)3. Then, calculate the amount of fertilizer to put in each hole:Pounds fertilizer per1,000 square feet = pounds of fertilizer per holeNumber of holes per1,000 square feetor(10 pounds ÷ 160 holes = 1/16 pound or 1 ounce per hole).4. Next, weigh out this amount of fertilizer, pour it into a paper or plastic cup and mark the level. Now you have a measuring cup to use to pour fertilizer into each hole.LIQUID SOIL INJECTIONSAssume you want to inject 32 ounces at each spot.1. Use the injector to apply water into a measuring container and count how long it takes to apply 32 ounces. Then just count off that number of seconds at each injection site to match that rate.2.By multiplying the number of injection sites per 1,000 square feet—use the same spacing as with drilling—you can determine the total amount of fluid you’ll use. For example, 32 ounces (0.25 gallon) x 160 sites per 1,000 square feet equals 40 gallons of solution (0.25 x 160 = 40).3.If you wanted to apply 3 pounds of N per 1,000 square feet, you would add 10 pounds of N to 40 gallons of water. To fertilize 5,000 square feet, you would add 50 pounds of fertilizer to 200 gallons of water.
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as high as 40 to 60 feet allow rapid coverage of large areas.Follow all fertilizations (except liquid feeding) with irrigation of at least 0.5 inch of water to move the fertilizer
into the turf root zone. Further, calibrate application equipment frequently to ensure you’re applying the correct
amount of fertilizer.FERTILIZING TREES AND SHRUBSIf you suspect a tree or shrub nutrient deficiency, remember that woody plant fertilization is not an exact science. Compared to turfgrasses, trees and shrubs do not provide easy-to-read deficiency symptoms. While trees and shrubs need the same essential nutrients as all other plants, deficiencies usually result in simple growth reduction. Specific symptoms, though less common, include:
• Stunted, small leaves• Leaf distortions• Dead spots• Early leaf drop.Many other factors can produce similar symptoms, so you should not jump to the conclusion that fertility is the problem. Plus, nutrient interactions can be complex and are not well understood. Excess levels of one can result in deficiency of others. In this case, the basic problem is an excess of a nutrient, not a deficiency.Unfortunately, tissue analysis is not always useful either. Researchers have not documented the relationships
between foliar symptoms, tissue-analysis results and fertilizer responses well enough to make meaningful recommendations in many cases. This does not mean tissue analysis is not useful—it often is vital for solving specific problems. However, our knowledge of tree nutrition
has not yet evolved to the point where it provides effective practical solutions to all nutrient problems. Because of the complexity of a plant’s nutrient status, many researchers caution that just-in-case fertilizing is not necessarily a good practice and could cause more harm than good. Many others, however, recommend regular fertilizing and have good results. At this point, no definitive word exists on what is the ideal practical approach to fertilizing trees and shrubs. The discussion below illustrates fertilizing practices according to those that recommend fertilizing annually. Unless symptoms become apparent, micronutrients are not usually necessary,
and annual applications should consist of N, P and K. But keep in mind that many authorities discourage the use of fertilizers on a “whether-it-needs-it” basis and recommend it only when trees and shrubs display lack of vigor or specific symptoms (see table, “Nutrient-deficiency
symptoms of trees,” page 76).Soil factors, as discussed, affect nutrient availability. In particular, pH above or below the 6.0 to 7.0 range can create unavailabilities. Another common problem for trees is competition with turfgrasses. If N is in short supply, trees usually suffer more than turfgrass growing in the same site. Research has repeatedly shown that fertilization at planting time has no effect. Container plants or smaller specimens that can rapidly establish may respond to fertilization within the first year. Larger trees do not respond to fertilizer for a few years, so wait until the third or fourth year after transplanting. Once established (this takes about 1 year for each inch of caliper), trees grow substantially faster with fertilizer. This is the time to concentrate most on fertility—after establishment, but while the tree is still young. Rapid growth is desirable at this time. As trees become mature,
they respond less to heavy fertilization but may still benefit from light amounts. By maintaining reasonable vigor, older trees are less vulnerable to pests and diseases. However, you should remember that fertilizing large trees may encourage growth of specimens that already are as large as the surrounding landscape can safely or aesthetically accommodate.Trees with restricted roots are special cases. Heavy fertilization may exaggerate their problems by increasing their shoot systems without a similar increase in roots. Unfortunately, fertilizer—including phosphorus—will not directly increase root growth in such trees and shrubs.TIMINGSome debate exists about the proper time to fertilize
trees. Traditional recommendations suggest spring or early summer applications. However, some research indicates that trees absorb nutrients more readily in the fall. Conversely, fall applications risk some of the N being unused and lost from the root zone while trees are dormant.
Apparently, neither time offers dramatically better benefits than the other. If you make fall applications, be careful not to over-apply N, which some arborists feel could delay fall hardening. When turf covers the root zone, trees may benefit more from spring fertilization, before turf begins rapid growth. Or, with warm-season turf, apply fertilizer in fall after turf has gone dormant. Both of these strategies prevent turf from taking as much of the N before it can move lower into the tree’s root zone.MATERIALS AND RATES Some recommendations base rates on trunk diameter, but fail to consider the area of application. If you use a
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diameter-based rate for a large tree in a restricted space, such as a planter, you may be adding enough salts to the soil to injure the tree. Tree-fertilizer materials are not fundamentally different
than turf fertilizers. Ratios of about 3:1:1 or 3:1:2 are best for tree fertilization. Use at least 25 percent slow-release N. Standard rates suggest 3 pounds of N per 1,000 square feet annually over the root zone. Evergreens should receive about half of that amount.For the fertilizer to be effective, it must reach the root zone. For most trees in most soils, the root zone is a uniform mat just below the soil surface. The small absorbing roots are in the top 4 to 8 inches of soil and extend from the trunk two or three times as far as the branches. Buildings, pavement and neighboring trees can restrict roots from spreading normally.# For surface applications, spread the fertilizer over the ground out to the drip line and then one-third farther. Afterward, lightly cultivate the soil with a rake. Water the area thoroughly after the application. Broadcasting soil-mobile elements, such as N, over the soil surface and watering them in supplies the entire root zone. However, you must apply soil-immobile elements such P and K through 8- to 12-inch deep holes.# Drill applications offer several advantages: They put P and K—nutrients relatively immobile in the soil—deeper into the root zone. They reduce turf competition for nutrients. They aerate soil and promote deeper rooting.Drill applications involve drilling 2-inch-wide holes 8 to 12 inches deep around the tree. You can use an electric drill with an auger bit or a gas-powered auger. Start about 3 to 4 feet from the trunk of large trees and extend to the drip line or slightly further. Drill applications do not require different rates of N than broadcast applications, but you must do some extra calculations to determine the application patterns (see “Drill-application rates,” at page 77). # Liquid injection is similar to drilling in that you place the fertilizer directly in the root zone. However, the fertilizer is, in this case, a liquid solution, and this method reduces the required time and labor. Use a sturdy gun with side-injection ports on the needle. These help distribute the liquid and prevent clogging. Use any spray rig that develops
the necessary pressure—150 to 200 psi.You can use as few as 8 or 10 gallons of solution or as many as 40 or 50 gallons. It’s more important to know how much fertilizer you’re injecting into each spot (see box, “Liquid soil injections,” below right). # Foliar applications. Applying nutrient solutions to foliage is a rapid, effective way to deliver nutrients to plants, which absorb them directly. However, the effects are relatively short-lived. Therefore, you should use this method in conjunction with soil fertilization for quick effect as well as longer-lasting fertility. Foliar applications consist of spraying foliage with the same equipment and techniques you’d use for spraying pesticides. You should spray to the point of runoff and ensure complete coverage. The use of surfactants may increase plant uptake. Foliage burn is possible with many products so do not exceed the recommended rate.# Trunk injections. Several techniques allow you to perform
trunk injections. One involves drilling holes and inserting injection tees. To these you attach tubes that deliver pressurized nutrient solutions into the sap stream. Another system operates by a similar principle with a small pressurized capsule attached to the feeder tube. A tap with a mallet breaks the seal and starts the injection. A third system also requires you to drill holes. But you then insert small capsules into the holes, tapping them in with a mallet or similar tool. The sap then carries the nutrients to other parts of the tree.The value of trunk injection is unquestionable where pesticides are concerned—it places them directly into the plant’s tissue to an extent difficult or impossible to achieve with external applications. Although trunk injections
also effectively deliver nutrients to the plant, many arborists feel that drilling holes in the trunk is not justified
when other effective techniques are available.TO LEARN MOREMany situations—golf courses, athletic fields, difficult
soil types—demand specialized fertility practices. To learn about specific practices in these situations, talk to other professionals in your area to see what works for them. Extension agents are another valuable source of recommendations and so are manufacturer representatives.
Finally, remember that each situation is unique: Tinkering with materials, rates and timing can help you find methods that work best for your site.
Pruning Trees & Shrubs
Pruning is the selective removal of plant parts to achieve a specific goal. Any pruning you perform should be for a definite reason and should remove no more than necessary
to achieve your objective. Often, people fail to realize that many trees and shrubs require little pruning to thrive and achieve good form. Some simply require the proper training when young and little more. A brief overview of woody plant growth will help you understand plant responses to pruning and when it’s appropriate.The portion of a trunk or branch that can actively grow consists of a small layer just inside the bark—the cambium. After a bud has initiated a shoot, the cambium gives rise to all new growth in the stem. When you prune, you leave a wound that mostly consists of tissue (wood) that cannot
grow and, therefore, cannot heal itself. Healing must commence from the perimeter of the wound, where the cut dissected the cambium. The cambium grows over the wound from the outside in, with a special kind of growth called callus (see Figure 1, at left). Because of this pattern, larger wounds take far longer to heal than smaller ones and so remain vulnerable to infection
longer. Your pruning choices should take this into account and minimize the size of the cuts you make. In practice, this means not only selecting the smallest possible branches to cut but also cutting
just above the branch collar, which we’ll discuss later in more detail.Another principle to remember
is that terminal buds (see Figure 2, below left) hormonally suppress the growth of lateral
buds lower on the branch. Thus, pruning that removes the terminal bud releases remaining
buds to grow. Pinching and heading back prompt branching
in this way. Stubbing larger branches often releases many dormant or latent buds, resulting
in a mass of new shoots. However, pruning to a lateral branch creates a new terminal that will function just as the old one you removed.The spot from which leaves, buds and lateral shoots arise is called the node. The space on the stem between nodes is the internode. This arrangement is easy to see on young shoots but becomes obscure on older branches.Pruning removes carbohydrate reserves (stored in wood), as well as foliage, which produces additional
carbohydrates through photosynthesis. Removing
these food sources reduces the plant’s ability to support its root system, which may die back if you remove too much of the shoot system. A tree may require several years to recover from severe pruning and the resulting stress makes it more vulnerable to pests, diseases and environmental extremes.A properly trained tree or shrub should never need severe corrective pruning. In reality, however, the landscape
professional often faces badly neglected plants that need a great deal of pruning to reacquire good form. Even if plant size is not an issue, crossing, dead, broken
or low-hanging branches and sucker growth may comprise a large portion of the crown. Although every species responds differently to the removal of large portions
of the crown, it generally is prudent to extend the process of corrective pruning over 2 or 3 years if you think you’ll need to remove more than about one-third of the crown.WHY WE PRUNEYou should not prune in a manner inconsistent with the natural form of the plant. For instance, you should never top trees that grow with central leaders. Even if you are unfamiliar with a species, a visual examination of the plant should give you some idea of its growth habit. The reasons to prune are several and may include:• Removal of crossing branches• Improving structural integrity• Influencing flowering and fruiting• Thinning to improve light and air penetration• Crown raising• Desuckering• Removal of dead or diseased limbs• Improving plant appearance• Training young plants• Controlling plant size.Let’s look at some of the specific ways we achieve these goals (see Figure 3, at left).# Removing crossing branches. Branches should be BDCCallusFigure 1. Callus is the tissue that heals over pruning cuts. Callus forms from the outside of the wound and gradually grows inward until it seals off the wound.AEFigure 2. The terminal bud (A) suppresses growth of lateral buds (B) below it. Removing the terminal bud releases lateral buds, allowing them to grow and produce new shoots. Make cuts just above a node (C). Cutting back to a lateral shoot (D) means its terminal bud (E) will become dominant.
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consistent with the general, natural form of a tree or shrub. Limbs that clash with this form disrupt visual appeal—spreading, horizontal branches clash with the form of an upright-growing tree, and upright branches conflict with a spreading form. Further, these branches often cross other branches and may rub against them, creating wounds that could lead to infection. Therefore, crossing branches are candidates for removal.# Improving structural integrity. Narrow crotch angles tend to produce weak unions and are prone to wind breakage. Removing the susceptible branch reduces the chance of it splitting off. Remove any other limbs that pose a hazard, such as those that show a crack, as well. # Influencing flowering or fruiting. Timing and severity
are the two aspects of pruning that most influence bloom. The section on “Timing” (page 84) discusses pruning times. Landscape professionals often prune shrubs that bloom on current growth rather severely to encourage more of the new growth that will bear flowers.# Thinning. Many trees and shrubs benefit from additional
light penetration to the inner leaves and branches, and increased air circulation also may help. Further, thinning
can improve the structural integrity of a plant. You also may wish to thin to emphasize attractive structural features of the plant.You should perform thinning cuts only after you’ve finished other pruning. That is, after you’ve removed crossing, dead, diseased and broken branches. Do not think that you must thin every time you prune. If, after you finish other cuts, the tree or shrub seems to have good balance and appropriate density, leave it as it is.The particular thinning cuts you make often are, to some extent, a matter of judgment. However, the appropriate
cuts are more obvious after you’ve made your other cuts. Some species branch more densely than others, so thinning cuts depend on the species in question.# Limbing up or crown raising. As trees age, branches become heavier and may hang so low they interfere with activities such as mowing or walking. These branches need removal and this is called limbing up or crown raising. This generally is a simple matter. Cut back to a strong lateral branch or clear to the trunk. Crown raising when trees are in full leaf is easier because you can see how low branches hang with the full weight of their foliage. Be careful not to cut back to laterals that are completely and deeply shaded by the canopy. These branches often die due to light deprivation and may require elimination
later.# Desuckering. Suckers—also called water sprouts—arise as vigorous shoots from the trunk or roots. Some species naturally tend to produce suckers while others produce few or none. Suckers usually grow contrary to the form of the tree and may end up crossing other branches. Plus, suckers often sprout from root stocks of a variety
different than that of the grafted cultivar. Thus, you always should remove suckers the same year they sprout. Hand shears generally are adequate
for this task.# Removing dead and diseased branches. If a branch has been dead for some time and the collar is healing around it, cut back to the living collar but no further, even if this leaves a large stub. You should allow the collar to continue to grow to seal off the dead wood. Remove diseased branches as soon as possible to prevent spread of the disease. This often is an effective practice if you cut well below the visible symptoms. However,
you should identify the disease before taking any steps. Having done so, you then can find more specific information on control measures—chemical remedies, sanitation and so on.Another point to remember is that when pruning diseased
branches, you may be contaminating your tools with a contagious disease. Therefore, disinfect your shears or saw between each cut to avoid spreading the disease to other plant parts or plants (see Chapter 15 for more information on disinfecting tools). # Improving plant appearance. This is a catchall category that actually encompasses many of the other reasons for pruning. Though references often cite “improving
appearance” as an objective of pruning—and this is inarguable—pruning for the reasons discussed above usually results in the desired plant appearance. However, even if it offends in no other way, you may wish to remove
the occasional odd branch that protrudes from a tree’s or shrub’s outline.# Training young trees. Pruning young trees is an important task that, if performed properly, produces a superior, relatively maintenance-free specimen in maturity. The first pruning. When you first plant a tree, the only pruning necessary is that which removes broken, dead or diseased branches, and root suckers. Although recommendations
in the past suggested pruning to balance the crown with the root system, research shows that this is not a wise practice. Any removal of branches other than those mentioned above will slow establishment. Branches BCACentral leaderWide angle branchFigure 3. This tree illustrates some typical pruning cuts. Eliminate weak (narrow) branching angles (A), suckers (B) and other limbs (C) that disrupt or protrude from the natural form of the plant. Most of the limbs on this tree show desirable wide branching angles. The central leader should not be removed.
82 TURF & LANDSCAPE DIGEST # 2004 chapter 11store food reserves, and leaves are the site of photosynthesis.
Thus, removing them eliminates resources the tree needs to grow a healthy root system and establish itself quickly. The second pruning. Allow 2 to 4 years for the tree to become established. Then, prune to remove problem branches (crossing, dead or diseased branches and those with weak branching angles) and half of the temporary limbs. Temporary limbs are those that branch from the trunk at a point lower than where you’ll want the lowest limbs on the tree when it’s mature. The exact height depends on the intended use of the site. Don’t remove too many of the temporary limbs at this time. For the tree to develop a healthy trunk taper, half of the young tree’s foliage should be on the lower two-thirds of the trunk. This distribution
and the resulting trunk taper provides strength and good wind resistance. After you’ve removed the temporary limbs, select the permanent scaffold limbs. Remove or cut back branches that turn in toward the trunk, extend beyond the natural outline of the tree or droop uncharacteristically. Then look for the healthiest limbs that are closest to being horizontal and are spaced 12 to 18 inches apart on the trunk. Remove limbs that are more upright or more closely spaced. The third pruning. Prune again 5 to 7 years after transplanting.
This pruning involves minimal cutting if you performed the previous work correctly. At this time, remove dead or dying branches, codominant leaders and root suckers. If any limbs protrude from the tree’s natural profile, head them back to a lateral branch within the tree’s crown. Also remove suckers and crossing
branches. # Controlling plant size. The need to reduce size implies that the plant was a poor choice for the site. Unfortunately,
this often is the case and reducing size may be preferable to outright removal. You should never reduce size by topping. Topping is so injurious to trees that many die within a few years of being cut. Others
that survive the short term may slowly decline. Unfortunately, topping is a common practice in spite of its detrimental effects.A better practice is to reduce size by drop-crotching
(see Figure 4, right). This entails cutting limbs back to lateral branches at least one-third to one-half the diameter of the branch you cut. This technique may require several years for significant size reduction, but it is the safest way to reduce
tree size. After you remove higher branches, lower branches will more quickly grow, and you then can cut back to these laterals in a year or two. Thus, over time, you can bring the height of the tree down considerably, but gradually and with much less trauma to the tree. The branches to which you cut should not diverge at an angle of greater than about 45 degrees and should point to the outside of the tree crown.Heading back, or stubbing, is another common technique for reducing size. Some references refer to heading as cutting back to a lateral branch. However, this essentially is no different than thinning or drop-crotching. We use heading here to mean cutting back to a stub. Heading back small branches (current or 1-year-old growth) is an effective
means of forcing young shoots to branch. However, heading larger limbs is a poor alternative to drop-crotching
and is no different from topping—it is damaging and results in vigorous sprout growth below the cut. These shoots are weakly attached and break off easily. Thus, they make undesirable replacement limbs.PRUNING TECHNIQUESThe same basic techniques apply to most types of pruning.
However, you need to adapt them to each specific kind of plant. Thus, there is no substitute for a thorough knowledge of plant material and the needs of each species. A good horticultural reference should provide pruning information specific to individual species.• Choosing cuts. Before you make each cut, visualize RightWrongBladeBladeFigure 5. When cutting back to a lateral, cut upward or sideways, as shown at left and below. Cutting downward may split the shoot. When removing a lateral (lower drawing), place the blade closest to the main shoot to avoid stubs.Figure 4. Drop-crotching, essentially the same thing as thinning, is the proper way to reduce tree size. The tree at left was reduced in size with thinning cuts without stubbing or otherwise harming its form.
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what the plant will look like afterward. This type of mental deliberation forces you to think about what you are doing and whether a cut will achieve your pruning objective. If the branch removal will leave a void, throw the plant out of balance or otherwise damage its appearance,
it probably is not a good choice unless
there is an overriding reason to remove the branch, such as disease.If you have a choice of which limbs to cut (all else being equal), choose the cut(s) that will produce the smallest wounds. One- and 2-year-old shoots have a high proportion of their mass in living cells that quickly react to environmental changes and usually have ample food reserves. Thus, shoot collars on young shoots react well to pruning wounds. Older shoots react more slowly to wounding because a greater proportion of their mass resides in declining inner annual growth rings. Pruning cuts on shoots that possess heartwood can lead to many problems. To minimize disease and decay, prune the youngest wood possible. The ideal pruning cut is one that heals and closes in the shortest time possible. Here are the basic principles involved in pruning most trees and shrubs:• Making clean cuts. Pruning wounds should always be clean; that is, they should be smooth and free of split wood, stripped bark and ragged edges. If you make a cut that leaves a ragged surface, clean it up with additional cuts. Dull or bent shears are a common cause of rough cuts.Trying to cut a branch that is too large is another reason a cut may not be as smooth as it should be. If you have trouble cutting a branch with shears, use a saw. Branches over 1 inch in diameter may be candidates for saws, although
some shears can accommodate branch diameters of 1.5 inches or even slightly larger. Saws will not leave a cut surface as smooth as shears, but a proper saw cut should still be reasonably clean.• Angle and position. When cutting a lateral with shears, position the hook to the outside of the cut (see Figure 5, at left) to avoid bruising the tissue remaining below the cut. With this positioning, the hook will press against the portion of the branch you’re eliminating. Also, this orientation
allows you to cut with the blade closer to the trunk or branch junction.When cutting back to a lateral, angle shear cuts up or sideways. This requires less effort on your part. Plus, this avoids branch splitting, which often happens when cutting downward at a branch junction. When heading back an unbranched shoot (see Figure 6, above left), cut diagonally
instead of at right angles to the branch. Again, this requires less strength and causes less damage to the stem tissue. Always cut just above a node. Cutting back to a lateral branch forces this to happen automatically because, by definition, this is where branches arise. When heading back young, unbranched shoots, cut 0.25- to 0.50-inch above the node, leaving a very short stub. Do not cut closer than this, as this will jeopardize the bud nearest the cut. However, if you cut too far above a node, you’ll leave an obvious stub because branching can only initiate from nodes. You can direct the growth of smaller branches by heading back to a bud oriented in the direction you wish growth to proceed.Avoid leaving long stubs when removing a lateral branch. Stubs may encourage disease and are unsightly. At the same time, you should take care not to cut too closely. Most branches exhibit a collar of tissue around the base of the branch (see Figure 7, above, middle). Never remove, cut into or otherwise damage the collar—it consists of tissue that will help heal over the wound left by pruning. Therefore, avoid flush cuts, which damage or remove the collar. For the same reason, you also should leave the bark ridges (which function like a branch collar) intact.With these concepts in mind, you can see that no one proper angle exists for every cut. The appropriate angle simply depends on the orientation of the collar or bark ridge (see Figure 8, above right).• Cutting large limbs. When cutting large branches (see Figure 9, above) with a saw, make the first cut about one-fourth of the way into the bottom side of the branch, several inches above the site of the final cut (the branch Branch-collar areaBark ridgeCutFigure 7. Preserve the branch collar or bark ridge when you prune. The dashed line indicates the proper cut. Cutting any higher will leave a longer stub than necessary. A flush cut will damage the collar.CorrectIncorrect45°45° angle Too angular Too low Too highFigure 6. Correct and incorrect heading cuts.Figure 8. Because the collar or bark ridge determines where you should cut, no single angle is appropriate for all pruning cuts. All of the cuts shown here are correct.
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collar). Then cut completely through the branch from the top side, just above the bottom cut. This way, when the branch drops, it will not pull a strip of bark from the trunk as it drops. You then can cut the remaining stub away without fear of damaging the trunk. Remove very heavy stubs with two cuts—the first from the bottom and the second from the top. Remember not to cut into the branch collar. Even on smaller limbs, it’s a good idea to make a shallow cut into the underside of the branch before cutting from the top to avoid stripping bark from the trunk as the branch falls.Cut narrow crotches that display a bark ridge in a similar but modified way. Cut away the branch, leaving a stub as just described. Then, cut from the bottom side of the junction upward at a 40- to 50-degree angle to the point of divergence (see Figure 10, right).Do not apply wound dressing or tree seal to pruning wounds. This is a practice that still persists to some extent, but research has not demonstrated benefits from wound dressing. At the very least, it is a waste of time and it may even encourage infection. TIMINGSeveral factors, such as flowering, and pest and disease problems, determine the proper time to prune.• Flowering. A general rule of thumb is to prune spring-flowering species in the summer (immediately after bloom) and summer-flowering species in the winter (before spring growth commences).Because spring-flowering plants bloom from buds that formed during the summer and fall of the previous season, pruning immediately after bloom allows season-long growth of the shoots that will bear the following year’s flower buds. Pruning them in the winter would simply eliminate the bloom for which you’re presumably growing the plant. Examples of spring bloomers include forsythia and redbud.Summer-flowering plants bloom from growth of the same year. Winter (dormant) pruning does not remove flower buds, which will not form until after growth commences
in the spring. Therefore, winter is the preferred time to prune summer bloomers. Examples include roses and crape myrtle.The proper time to prune—other than when dictated by flowering—is open to some debate and may not be critical in many cases. However, most authorities agree that springtime—during the growth push—is not a good time. Summer and winter pruning both may produce acceptable results.• Winter pruning. Minimizing the length of time pruning
wounds remain open is an important consideration. By this logic, winter or early spring—just before spring growth starts—is the best time to prune. Healing starts as soon as spring growth begins.An advantage of winter pruning is that leaves of deciduous plants have fallen and the branch structure is more visible. This makes it easier to choose your cuts. Also, pests and diseases
are inactive in most regions during the winter and so cannot take advantage of fresh pruning wounds to gain entry into the plant. In any case, winter is a convenient time to prune, because it is a less busy time. For these reasons, landscape professionals usually—and properly—think of pruning primarily as a dormant-season activity.• Summer pruning. In summer, when plants are in full leaf, you can see dead or diseased branches more easily. Further, foliage weighs on low limbs so you can better decide which of them may interfere with activities by hanging low. Pinching to encourage branching and sucker removal are other types of pruning that you may wish to perform in the summer. Thus, some types of pruning are appropriate during summer. Authorities do not generally recommend autumn as a time to prune. Pathologists note that many pathogenic fungi sporulate at this time, possibly rendering pruning wounds more susceptible to infection. However, trees that are prone to bleeding from pruning wounds—such as birch, elm and maple—may bleed much less if you make cuts in autumn. Even though bleeding usually is harmless First cutFinal cutSecondcutFigure 9. Cutting large branches involves three cuts. Make the first cut on the underside of the branch, several inches above the point of the final cut (the collar). The second cut should be slightly above this but on the top side of the branch. This cut should go all the way through the branch, until it drops. The last cut will remove the stub.Figure 10. Leave the bark ridge intact when pruning in narrow crotches. Cut to a stub, as you would with the first two cuts depicted in Figure 9. Then remove the stub with a 40- to 50-degree cut extending from the bottom to the approximate point of connection in the crotch. Note that the woody connection often is much lower than it appears. The area between the arrows does not possess a woody connection.First cutSecondcutThirdcut
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to plants, it can be unattractive. Therefore, fall pruning may be a solution if you wish to minimize bleeding.Fresh pruning wounds may attract some wood-boring insects. It is worthwhile to check with a local extension adviser for advice on when to prune species susceptible to borers in your region.SHRUBSShrubs generally require pruning for much the same reasons—and by the same principles—as trees. However, controlling size is a more frequent concern with shrubs, especially those growing near structures or walkways. In these cases, a regular pruning schedule may be necessary to avoid the need for larger cuts. Shrubs also are commonly
sheared, which we’ll discuss later.Some professionals provide “rejuvenation” or “renewal” pruning to old, large shrubs that seem to have lost their vigor but display no other symptoms. This involves stubbing
the plant back to a few large branches, often close to the ground, and relies on resprouting to reestablish a new framework of branches. Such harsh treatment often succeeds, but it is not recommended unless the shrub has declined to the point where this is your only option. You can do this gradually by removing one-third to one-half of the old branches the first year. The second year, new shoots will have grown, and you can remove the remaining old branches without completely denuding the plant.Shrubs that produce new shoots from ground level often succeed best with basal pruning. That is, removing large or declining shoots at ground level. This controls height, keeps the plant thinned, avoids stubs and often requires less labor. Forsythia and Nandina domestica are common examples of shrubs that work well with this treatment.Roses require cane pruning. This entails cutting the branches back to several 1-year-old canes each year during
dormancy, with the uppermost bud pointing outward. The length and number of canes you leave depends on the vigor of the plant and how much new growth you wish to encourage (remember, roses flower on new growth). References dealing entirely with roses discuss this type of specialty pruning in great detail.CONIFERSConifers whose branches grow in whorls, such as some pines and spruces, often require little pruning except for the occasional dead or broken branch and perhaps limbing
up. However, you may wish to force more branching in some species by pinching out parts or all of the new shoots, or candles. Pruning whorled conifers must consist of either this or cutting back to a lateral branch. Heading back into old wood, even if it still bears foliage, will not force any new branching, leaving a stubbed plant. Random-branching conifers—junipers and yews being two examples—are not so limiting. These conifers can produce shoots from older latent buds. However, avoid stubbing bare wood; these branches will not produce new shoots (yews are an exception to this rule).PALMSPalm trees do not normally require pruning for their own benefit, except for transplants. Landscapers typically prune off fronds of transplanted palms, leaving several at the top to protect the tender apical bud. On established palms, however, older fronds either fall or remain attached
to the trunk as they die, but they do not affect the health of the tree if they remain on it. Still, for the sake of a tidy appearance and to prevent fire hazard, landscape professionals typically remove older fronds from ornamental palms as the leaves age.If the fronds are still green, some pruners use a pruning
knife on the stalks. However, chain saws are the tool of choice for frond removals on most species and can produce an attractive appearance with the cut frond bases. However, the chain saw may be prone to clogging from palm fibers. Enlarged chain housings help alleviate this problem. The palm trunk itself requires no pruning, and you should never disturb the apical bud, which is hidden within
the emerging leaves. Most palms only possess one apical
bud, and the tree will die if it is lost. Clumping palms with multiple trunks occasionally may need containment. If so, remove entire trunks to their base. Stubbing a trunk will not result in any new shoot production. Some palms, such as coconut palms, require fruit removal
for obvious safety reasons. This may be necessary as often as every few months. SPECIALIZED PRUNING TECHNIQUES• Shearing and hedging. Shearing provides a formal or well-defined shape to shrubs and hedges. Shearing requires
either hand shears or powered shears, the latter being preferred for large jobs. After a hedge has been planted, shear off the top one-third of each season’s growth until the plants reach the desired size. This shearing will prompt the plants to branch and fill in more quickly.Once the hedge reaches maturity, shear off nearly all of the new growth two or three times a year, as needed. However, to maintain fresh foliage and good density, you’ll need to retain 0.25 to 0.50 inch of the new growth Good shape Acceptable shape Good shape Poor shapeFigure 11. Hedges should taper to a narrower top. This allows light to reach lower branches.
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each time you shear. This means that the hedge will gradually increase in size. Therefore, you must periodically
perform severe pruning to reduce the size of the hedge. Species tolerant
of hedging generally recover
well from such treatment.
Do this just before new growth occurs, such as in early spring, to minimize
the length of time the hedge is bare.The top of a hedge should be slightly narrower than its base. This allows light to more effectively reach the lower branches and prevent them from dying out (see Figure 11, 85).Irregular or curved shapes require the pruner to have some experience to produce the desired result. Practice, patience and a steady hand are the necessary ingredients. Squares, rectangles or long, straight hedges are somewhat easier to prune because you can rig reference lines to guide your cut. Simply run twine between two stakes at the level you wish to make the cut, and use the twine as a guide. Be careful not to entangle the line. For even greater precision, use a line level to ensure the cut is even and level. Use long sweeping strokes as you shear hedges with a power trimmer.• Pollarding. Pollarding (see Figure 12, above) is a unique type of annual pruning that can help the landscape manager
meet the aesthetic and size-constraint objectives of a landscape. Although it is a high-maintenance procedure, pollarding allows you to save and maintain valuable landscape trees at a small to medium size indefinitely with little loss of health or structural integrity. Other tree-crown reduction techniques, depending on the tree species and the size of branches you remove, may initiate structural problems that can lead to catastrophic failure in storms or under ice glazing.To begin a pollard, make the first cuts at a twig or branch junction where the side branch is at least one-third the diameter of the stem you’re cutting (see Figure 12, above). By the next year, dormant and adventitious growing
points usually begin to grow close to the pruning wound. You then can prune off the remaining branch or twig that extends past the point from which new shoots are growing (see Figure 13, above right). Also remove sprouts that begin growing anywhere else in the tree. At the branch or twig tip, remove most of the sprouts but leave one or two until the following year. Be sure to avoid cutting into the shoot collar at its base. Pollarding has now begun.Over time, annual
pollarding will result in the buildup of a head or knot at the pruned end of the branch. This swollen clump, composed of the structural and defensive
collar areas of many pruned shoots, is the characteristic feature of a polled tree. Never cut into or behind this swollen area of current and old shoot collars. Nor should you leave shoot stubs. In other words, proper pruning practices still apply to pollarding.The age of the shoot you choose to pollard is critical to developing a structurally sound and healthy polled tree. One- and 2-year-old shoots react well to pollarding. Thus, to minimize disease and decay, prune the youngest wood possible and maximize the ability of the tree to react to wounding by implementing a health-maintenance program.
Pollard trees annually once begun.If possible, start pollarding when trees are young. Because pollarding is highly stressful and stunting to a young tree, select good-quality trees growing on good sites for best success. Allow young trees to become established at their sites for at least 3 to 5 years before initiating a pollarding program. For best results, a tree should be no more than 2 to 5 inches in diameter with a large proportion of its height in living branches. Initiate pollarding on the youngest branches possible.Remember, pollarding should keep a tree the same size for its entire life. Therefore, you should carefully consider every pruning cut from the first heading or crown-reduction
cut. You must establish proper height from the start. Young trees you have trained to the required height and form from the beginning will perform better than retrofitted mature trees. Failure to continue pollarding, once begun, leads to tree loss.• Espaliers, pleaching and topiaries. An espalier consists of a branch framework trained to occupy a vertical plane, usually on some sort of trellis (see Figure 14, opposite page). Pleaching consists of weaving or intertwining branches to form various configurations, often that arch or otherwise overhang. These rather artistic forms of training require a great deal of attention. They necessitate
extensive pinching and tying of branches to strong supports, such as a wood or wire trellis. Eventually, these plants may or may not be self supporting, depending on their structure and the type of plant.Topiaries are plants you shear to attain specific shapes or designs that mimic animals, symbols or other shapes. Topiaries often use wire to hold branches in position or as a framework for vining plants. Shearing topiaries is Figure 13. The next year, you can cut the lateral, as well as most of the new shoots, back to the head. Pollarding has now begun.Image for Figure 14 is not available to use in this issue.Figure 12. To start a pollard, cut back to a lateral at least one-third the diameter of the branch you’re cutting. This will force new shoots to grow below the cut.
2004 # TURF & LANDSCAPE DIGEST 87
not fundamentally different from other types of shearing, but it requires skill and experience. Consult references dealing with these specialized types of pruning for more detailed information.PRUNING TOOLSQuality tools are necessary for good pruning, and you must maintain your tools properly for them to remain useful. Several factors influence your choice of pruning tools for a particular job: branch size, hardness of wood, height above ground and so on. Landscape professionals usually possess a variety of shears and saws for different situations (see Figure 15, page 88). The basic pruning tools include:• Hand shears. Hand shears are designed for light pruning of branches up to 0.75 inch in diameter. Many grounds-care professionals routinely wear a leather belt and holster so that their hand shears are available for on-the-spot use for removal of small branches, deadheading and many other tasks.Two basic types of hand shears exist: anvil-type shears and hook-and-blade shears. Anvil shears—also called snap-cut pruners—possess a sharp blade that cuts against a broad, grooved surface—the anvil. Hook-and-blade shears—sometimes called draw-cut or bypass shears—are the more commonly used of the two types and employ a scissors-type action to make cuts. Many professionals feel that hook-and-blade shears produce cleaner cuts with more precision. Both types are available in a variety of sizes, and styles are available for specialized tasks such as pruning miniature plants.Hand shears vary in price and quality, but you will find that high-quality shears usually are worth the cost. They produce cleaner cuts, and they are more durable as well. Further, you usually can obtain replacement parts if they break.Ratchet shears use a special mechanism to increase leverage,
reducing the force you must apply to make the cut. This may be of use to those with weak grips, but ratchet shears are not in widespread use among professionals because they tend to be less durable than conventional shears.• Lopping shears. Sometimes simply called loppers, these two-handed shears are another of the basic tools of the landscape professional. The longer handles extend the pruner’s reach and allow you greater leverage for cutting
larger branches. Loppers range in length up to 36 inches or more.Similar to hand shears, hook-and-blade and anvil types are available, but the latter is preferred for professional use. Handles are made from steel, aluminum, fiberglass or wood. Although wood is perhaps most popular, the other materials have advantages as well. In particular, they are resistant to breaking. However, you can replace wooden handles if they break, and their flexibility and light weight make them easy to use. Thus, your choice of material for lopper handles mainly is a matter of personal preference. Rubber bumpers are a feature that greatly increases user comfort. Some manufacturers employ gear mechanisms that increase the cutting force of the shears, allowing you to cut harder wood or larger diameter branches. • Pole pruners. Pole pruners consist of a pruning head and an extension pole. The head combines a saw blade and cutting shears the pruner operates with a pull rope. Some units allow you to replace the head with a large saw blade for cutting bigger limbs. The pole may be a single, rigid unit, but more often consists of telescoping sections that provide various working lengths up to 18 feet on the longer units. Poles usually consist of aluminum, but fiberglass and wood units are available, and these are preferable for work near power lines. Electrical lines pose a grave risk to workers using aluminum pole pruners.Whenever you use a pole pruner, use caution. Limbs dropping from above are dangerous, and falling sawdust and other debris can cause eye damage.• Pruning saws. A wide variety of pruning saws exists. Many are specialized for a particular type of job, and others are designed for more general use. Some saws cut on the pull stroke (useful for typical pruning on living wood), some on the push stroke (such as a tree-surgery saw used for heavy work on large branches), and some cut both directions.Additionally, the size and number of teeth vary. Saws with smaller and more numerous teeth are suitable for smaller branches, or dead or hard wood. Two-edged saws have large teeth on one side of the blade and small teeth on the other (which poses the risk of accidentally
cutting into desirable branches during use). Speed saws with raker teeth replace every fifth tooth with a slot or a raker to prevent jamming from sawdust on large cuts. A speed saw with lance teeth is recommended for large deadwood. Saw blades are cut from steel, and many have a non-stick coating to resist rusting and reduce friction.Figure 14. Examples of popular espalier forms.Belgian fenceCandelabraHorizontal cordon
88 TURF & LANDSCAPE DIGEST # 2004
chapter 11Aside from the configuration of the saw teeth, pruning
saws come in many designs. Curved saws with rigid handles are common, as are folding saws. Folding saws may require a screwdriver for tightening or they may use a wingnut. A disadvantage of folding saws is that the blade can work loose and cause the saw to collapse during use.Bow saws are efficient for large branches but awkward in tight spaces. Thus, they are more appropriate for firewood
cutting than everyday pruning.• Chain saws. Chain saws employ saw chains on a cutting bar and usually are powered by a gasoline engine (electric models are available as well). Chain saws are indispensable for cutting larger limbs. They are fast and less tiring than handsaw pruning. However, because of their size, weight and configuration, there is a limit to the cutting precision chain saws can provide. Further, pruners need to exercise great caution when using these tools—chain saw accidents cause many injuries each year. Thus, although chain saws are tremendous labor savers, avoid the temptation to use chain saws when a hand saw would produce a better, safer cut without undue effort. Always wear proper safety equipment
when using chain saws—chaps, gloves, a helmet, boots, and ear and eye protection. • Hedge shears. For pruning hedges or shrubs to a formal shape, you need hedge shears. Hand-powered hedge shears use two sharpened, broad blades that move with a scissors action to produce an even, flat cut. Many models also possess a limb notch for cutting slightly larger branches you may encounter while shearing. Handles range in length from about 10 inches to 2 feet or more for extended reach. Rubber shock absorbers increase user comfort.Hedge shears powered by electricity and gasoline engines
are widely available. These employ an oscillating sickle bar with sharpened teeth that produces shearing action as it moves back and forth past the teeth of a stationary
bar. Gasoline-powered shears are preferred for large jobs and professional use because of their speed, power and portability compared to electric units. However,
electric units offer the advantage of low noise and therefore also have a place in professional use when you must keep noise to minimum.• Tool maintenance. All pruning tools require some maintenance. Sharpening is the most common upkeep procedure you’ll need to perform. Sharp tools are far more effective than dull, neglected pruners so this is a matter that needs periodic attention. Sharpening is a relatively simple matter for shearing tools, which you can hone with a file and a whet stone. However, sharpening saws requires some skill and precision. If you are not experienced at sharpening saws, it is better to leave this task to a professional.A coating of diesel oil, lubricant or other rust-inhibiting
product prevents rust from forming on pruning tools. Apply such materials periodically to metal parts prone to rusting.Most shearing-type tools have adjustments (screws or nuts) that control how close the blades pass to one another. If the adjustment is too loose and the gap between
blades (or the blade and anvil) too large, wood will wedge between the hook and the blade during cutting. This causes slight bends in the metal and can render pruners
nearly worthless. Thus, this is a factor that requires close, frequent attention.SAFETYPruning involves some of the most potentially hazardous
situations in the landscape-maintenance field. Accidents
with chain saws and pruning shears are common and, all too often, tragic. Even small shears can sever fingers, and chain saws pose an obvious and potentially lethal hazard. Eye injuries frequently occur when sawdust or other foreign material falls into the pruner’s eyes. Receive
proper training before using a chain saw or other power equipment. Gloves and eye protection always are a necessity when pruning. When you use power equipment such as chain saws or power hedge shears, ear protection, a hard hat and chaps also are necessary. Electrical lines are a common hazard for tree pruners. Never use a metal pole pruner near power lines, and exercise common sense to avoid any possibility of electrocution.
Remember, electricity can arc from lines—you do not actually have to touch them. Pruning near utility lines is a job best left to those experienced and equipped for this type of pruning.Climbing trees also is a dangerous activity. If you do not have the proper training to climb trees, leave the job to someone who does, or use a hydraulic lift. Using ropes and other special climbing equipment takes experience
and skill. However, these are necessary to avoid the damage of climbing spikes, an inexcusable practice harmful to trees.TLDHand prunersPruning sawHand prunersHedgeshearsLopping shearsFigure 15. Various types of pruning tools.
2004 # TURF & LANDSCAPE DIGEST 8chapter
12PRECAUTIONARY STATEMENTSHAZARD TO HUMANS AND DOMESTIC ANIMALS(Signal word)ENVIRONMENTAL HAZARDSPHYSICAL OR CHEMICAL HAZARDSDIRECTIONS FOR USEIt is a violation of federal law to use this product in a manner inconsistent with its labeling.RESTRICTED-USE PESTICIDERE-ENTRY STATEMENT(if applicable)STORAGE ANDDISPOSALSTORAGE:PESTICIDE DISPOSAL:CONTAINER DISPOSAL:RESTRICTED-USE PESTICIDEDue to (reason here)For retail sale to and use only by Certified Applicators
or persons under their direct supervision and only for those uses covered by the Certified Applicator’s certification.PRODUCT NAMEEPA Registration No.___________ [Registrant name]EPA Establishment No.__________ [Address, City, State, Zip code]SEE SIDE PANEL FOR ADDITIONAL PRECAUTIONARY STATEMENTS.STATEMENT OF PRACTICAL TREATMENT (First aid) If swallowed:If inhaled:If on skin:If in eyes: Signal word POISONActive ingredient(s) ............................................... _____%Inert ingredients .................................................... _____%Total ..................................................................... 100.00% This product contains ___ lbs of _______ per gallon.KEEP OUT OF REACH OF CHILDRENCROP SITECROP SITECROP SITECROP SITECROP SITECROP SITECROP SITEWARRANTY STATEMENT################8##13##Figure 1. Use this information to identify the parts of labels for restricted-use pesticides. 1 “Restricted-use pesticide” identification 2 Statement of pesticide classification 3 Product trade name 4 List of active and inert ingredients 5 Pounds-per-gallon statement (if liquid) 6 Child-hazard warning 7 Signal word: Danger, warning or caution 8 Skull and crossbones and word Poison in red 9 Statement for medical treatment 10 Referral statement11 EPA pesticide registration number12 EPA registrant/manufacturer establishment
number13 Registrant’s/manufacturer’s name and address14 Statement of net contents15 Side- or back-panel precautionary statements16 Hazards to humans and domestic animals17 Environmental hazards18 Physical or chemical hazards19 Directions for use (and misuse) statement20 Re-entry statement21 “Storage and disposal” informationSource: Environmental Protection Agency, Biopesticides and Pollution Prevention Division.2012Net contents:________1410##1211195643215161719187APesticides & Pesticide LabelingApplying pesticides correctly and safely requires knowledge and skills. It carries a load of special responsibilities.
As one who applies pesticides or supervises
other pesticide applicators, you must be sure pesticides are handled properly and safely. You must be familiar with all state and federal laws regulating the use, storage, transportation, application and disposal
of pesticides. Federal laws and regulations set the standards for pesticide use. States have the right to be stricter than federal law but not more lax. At the national level, the U.S. Environmental Protection Agency (EPA), established
by the U.S. Congress in 1970, regulates the use of pesticides under the mandate of the Federal Insecticide,
Fungicide and Rodenticide Act (FIFRA). FIFRA
& LANDSCAPE DIGEST # 2004 chapter 12was enacted in 1947 replacing the Federal Insecticide Act of 1910 and has been amended several times since then. The U.S. Department of Agriculture (USDA) regulated pesticides before EPA.FIFRA governs the registration of pesticides. No manufacturer can market a pesticide in the United States until EPA approves the registration request from the chemical company (registrant) wishing to market it. EPA bases registration decisions on data, submitted by the registrant, demonstrating that the pesticide will do what it is marketed to do and that the use will not result in “unreasonable human health or environmental effects.”
Pesticides play an important role in the control of turf and landscape pests. As defined in FIFRA, pesticides are: “Any substance or mixture of substances intended for preventing, destroying, repelling or mitigating any insects,
rodents, nematodes, fungi or weeds, or any other forms of life declared to be pests, and any substance or mixture of substances intended for use as a plant growth regulator (PGR) (see table at left), defoliant or desiccant.” According to the EPA, "The term pest means any insect, rodent, nematode, fungus, weed or any other form of terrestrial or aquatic plant or animal life or virus, bacteria
or other micro-organism (except viruses, bacteria or other micro-organisms on or in living man or other living
animals) which the Administrator declares to be a pest under section 25(c)(1)." Like medicines people use to ward off diseases, turf and ornamental pesticides are actually plant medicines. “Pesticide” is a general term that refers to several different
products that control specific pests. Pesticides include insecticides that control insects, herbicides that control weeds and fungicides that control disease-causing fungi. They also refer to bactericides that control disease-causing bacteria, algicides for controlling algae, nematicides
for controlling nematodes and miticides for controlling
mites. PESTICIDE LABELINGPesticide product labeling is the main method of communication
between a pesticide manufacturer and pesticide
users. The information printed on or attached to the pesticide container is the label. Labeling includes the label itself, plus all other information you receive from the manufacturer about the product when you buy it. The labeling may include brochures, leaflets and other information that accompanies the pesticide product. Pesticide labeling gives you instructions on how to use the product safely and correctly. Pesticide users are required
by law to comply with all the instructions and directions for use in pesticide labeling. When you purchase a pesticide, your first step in using the product is extremely basic: Read the label. The importance
of this step cannot be stressed enough. The pesticide label is a legal document; its restrictions are enforceable. It provides information for the safe handling and proper use of a pesticide. It is your single-most important tool in using the product safely and effectively. Not only does it include information regarding application procedures and preventive measures, but it describes ingredients and antidotes.PESTICIDE TOXICITY CATEGORIESCategoryToxivity levelSignal wordIHighly toxicDanger, PoisonIIModerately toxicWarningIII Sightly toxicCautionIVRelatively non-toxicCautionPGR SOURCES1Active ingredientBrand (manufacturer)CytokininAgriplex PGR for T&O (Agrisel USA)Dikegulac-sodiumAtrimmec (PBI/Gordon)EthephonEthephon 2 (Top Pro)Florel (Monterey)Pistill (Monterey) Proxy (Bayer)ProTrim (LESCO)FlurprimidolCutless (SePRO)Gibberellic acidProGibb (Valent U.S.A.)Indole-3-butyric acidSnipper (Tree Tech)MefluidideEmbark T&O, Embark 2S (PBI/Gordon)Sta-Lo (Opti-Gro)Mefluidide + imazethapyr
+ imazapyrStronghold (PBI/Gordon)Methyl chlorflurenolMaintain CF 125 (PBI/Gordon)Naphthalene acetic acid (NAA)Sucker Stopper Concentrate/ RTU (Monterey)Tre-Hold (Amvac)PaclobutrazolTGR (Andersons)2Trimmit (Syngenta)Trinexapac ethylPrimo (Syngenta) Triple Play (LESCO) 31 No endorsement is implied by this listing, nor is criticism implied by omission. 2 Available in combination with granular fertilizers, as well as singly as a liquid.3 Combination with chelated iron + fertilizer.CONTACT INFORMATIONAgrisel USA Inc.—(877) 480-0880—www.agrisel.com Andersons—(800) 225-2639—www.andersonsgolfproducts.com Bayer—(800) 331-2867—www.bayerprocentral.comLESCO—(800) 321-5325—www.lesco.comMonterey—(559) 499-2100—www.montereychemical.comOpti-Gro—(800) 527-9919—www.opti-gro.comPBI/Gordon—(800) 821-7925—www.pbigordon.comSePRO—(800) 419-7779—www.sepro.comSyngenta—(800) 334-9481—www.syngentaprofessionalproducts.comTop Pro—(800) 888-5948—www.topprospecialties.comTree Tech—(352-528-5335—www.treetech.netValent U.S.A. —(800) 89-VALENT (898-2536)—www.valent.com
2004 # TURF & LANDSCAPE DIGEST 91
PESTICIDE SOURCESA variety of products exists for most pest-control needs. You can use recommendations from manufacturer representatives,
extension agents or pest-control advisors to determine the appropriate pesticides for your situation. In addition, various references also are available to help you make such pest-control decisions. For example, Grounds Maintenance magazine annually publishes its “Chemical Update” series. The tables on pages 93, 95 and 96, drawn from the 2004 “Updates,” list brands and manufacturers of pesticides to help you locate sources for chemicals (changes may have occurred since this information was compiled). However, never forget that it ultimately is your responsibility to apply pesticides properly—read the label of every pesticide you use and follow its instructions exactly. GOVERNMENTAL REQUIREMENTSEmphasizing the importance of label use, FIFRA dictates several provisions regarding pesticide use. FIFRA states:1. Users cannot use any pesticide in a manner that is inconsistent with the label. For example, you only can use a product on sites that appear on the label. In addition, this provision means that you can’t use a product at a rate that is greater than that specified on the label.2. The government can fine or imprison growers,
applicators or dealers who deliberately violate the label restrictions.Chemicals are classified as restricted use or non-restricted use. Figure 1 (see page 89) shows an example of a restricted-use pesticide label for a highly toxic (Category I) chemical product.In addition to federal regulations, states may require supplemental labeling, which you must follow as well.THE IMPORTANCE OF CERTIFICATIONObviously, chemical manufacturers must comply with strict government requirements when labeling their products. But you, the user, must comply with government regulations
as well. In fact, for those products labeled as restricted use, FIFRA allows only certified applicators—
or persons under their direct supervision—
to purchase or use those products. The certified applicator’s certification also must cover the chemical’s uses. (The restrictions
on this requirement vary from state to state, so check with your local governmental authority on how this aspect applies to your business.) For certification, the test typically covers—among other topics—areas such as:• The general format and terminology of pesticide labels and labeling• Information that typically appears on pesticide labels• The pesticide’s classification (whether it is a restricted-use or non-restricted-use product)• The importance of using the pesticide consistent with its label instructions.DETERMINING RESTRICTED USEThe classification of a pesticide as a restricted-use chemical is independent of its toxicity category. For example,
the manufacturer might register a chemical as Toxicity Category III—which means it is not very toxic to humans. Nevertheless, this chemical might be highly toxic to birds. Therefore, EPA would restrict its use to only certified applicators. Another manufacturer might register a chemical as Toxicity Category I—highly toxic to humans. However, because of its formulation or use pattern, EPA may not require that the chemical manufacturer
register this product as a restricted use. Why? Because the chemical may be only toxic to the eyes, so a COMMON PESTICIDEFORMULATIONSEC—Emulsifiable concentrate. A liquid consisting of an oil-based pesticide with emulsifier added to facilitate mixing with water.F—Flowable suspension. A wettable (but not soluble) powder suspended
in a water-based carrier. Agitation may be necessary.Gel—A gelatinous pesticide suspension, emulsion or solution, often used in water-soluble packets or closed, returnable-container
systems.G—Granular. Dry granules consisting of the pesticide and an inert carrier. Coatings are sometimes used to control release rate.S or SC—Salt concentrate. A true solution formed by water and the salt derivative of a pesticide. No agitation is needed.SP—Soluble powder. A dry powder that forms a true solution when mixed with water. Tank agitation is not required. W or WP—Wettable powder. A powder composed of a low-solubility
pesticide with inert fillers and, usually, a surfactant to enable mixing with water. Agitation is necessary.WSP—Water-soluble packet. Measured amounts of soluble powder or granules in a packet that dissolves in water. No agitation
is required.WDG—Water-dispersible granule. A low-solubility pesticide in granular form that quickly disperses in water. Tank agitation is necessary.
92 TURF & LANDSCAPE DIGEST # 2004 chapter 12
precaution to wear goggles is sufficient to protect the applicator.If the EPA does not require a manufacturer to register a pesticide as a restricted-use chemical, then that statement—
restricted use—does not appear on the label. Also, whether the skull and cross-bones and the word Poison appear on the label depends on the toxicity category and not the classification.FORMULATIONSThe active ingredients in a pesticide are the chemicals that control the target pest. Most pesticide products you buy also have other ingredients, called inert (inactive) ingredients.
They are used to dilute the pesticide; to make it safer, more effective and easier to measure, mix and apply;
and to make it more convenient to handle. Usually the pesticide is diluted in water, a petroleum-based solvent or another diluent. Other chemicals in the product may include wetting agents, spreaders, stickers or extenders. This mix of active and inert ingredients is called a pesticide formulation. Some formulations are ready for use. Others must be further diluted with water, a petroleum-based solvent or air (as in air blast or ultra-low volume [ULV] applications) by users before they apply them. A single active ingredient often is sold in several different
kinds of formulations. If you find that more than one formulation is available for your pest-control situation,
you must choose the best one for the job. Before you make the choice, ask yourself several questions about each formulation:• Do you have the necessary application equipment?• Can the formulation be applied safely under the conditions in the application area?• Will the formulation reach your target and stay in place long enough to control the pest?• Is the formulation likely to harm the surface to which you will apply it?To answer these kinds of questions, you need to know something about the characteristics of different types of formulations and the general advantages and disadvantages
of each type. LIQUID FORMULATIONS# Emulsifiable concentrates (EC or E). An emulsifiable concentrate formulation usually contains a liquid active ingredient, one or more petroleum-based solvents and an agent that allows you to mix the formulation with water to form an emulsion. Each gallon of EC usually contains 25 to 75 percent (2 to 8 pounds) active ingredient.
EC’s are among the most versatile formulations. They are used against a range of agricultural, turf and ornamental,
forestry, structural, food processing, livestock and public-health pests. They are adaptable to many types of application equipment, from small, portable sprayers to hydraulic sprayers, low-volume ground sprayers, mist blowers and low-volume aircraft sprayers.Advantages of using ECs:# Relatively easy to handle, store and transport# Little agitation required—will not settle out or separate when equipment is not running# Not abrasive# Does not plug screens or nozzles# Little visible residue on treated surface.Disadvantages of using ECs:# High concentration makes it easy to overdose or underdose
through mixing or calibration errors# May cause unwanted harm to plants# Easily absorbed through skin of humans or animals#Solvents may cause rubber or plastic hoses, gaskets and pump parts and surfaces to deteriorate# May cause pitting or discoloration of painted finishes.# Solutions (S). Some pesticides’ active ingredients dissolve readily in a liquid solvent, such as water or a petroleum-based solvent. When mixed with the solvent, they form a solution that will not settle out or separate. Formulations of these pesticides usually contain the active ingredient, the solvent and one or more other ingredients. Solutions may be used in any type of sprayer indoors or outdoors.Some solutions are ready-to-use (RTU) products that contain the correct amount of solvent when you buy them. No further dilution is required before application. These formulations, usually solutions in petroleum-based solvents, contain small amounts (often 1 percent or less) of active ingredient per gallon.Other solutions are sold as concentrates (C or LC) that you dilute with a liquid solvent before you apply them. Occasionally the solvent is water, but more often the solvent is a specially refined oil or petroleum-based solvent.Some uses of solutions include:• Structural pest control• Shade-tree pest control• Mosquito control.Advantages of using solutions:# No agitation necessary# Relatively easy to handle, store and transport# Little agitation required—will not settle out or separate when equipment is not running# Not abrasive# Does not plug screens or nozzles.Disadvantages of using solutions:# Limited number of formulations of this type available.
2004 # TURF & LANDSCAPE DIGEST 93
SOURCES OF HERBICIDES1For contact information for suppliers listed here, see next page. This listing is not intended as an endorsement by the publisher or author, nor is any criticism intended by ommission.Blue type indicates new chemical for the turf and ornamental market.COMMON NAMETRADE NAMES (SUPPLIERS)1Ammoniated soap of fatty acidsQuick-Fire (Monterey)AsulamAsulox (Bayer)AtrazineAtrazine (LESCO, UHS)Atrazine Turf & Conifer (Sipcam Agro)St. Augustine Weedgrass Control (Andersons)BenefinBalan (Andersons, Dow AgroSciences, Howard Johnson’s, LebanonTurf, UHS)Benefin + oryzalinXL 2G (Helena, Howard Johnson’s)Benefin + trifluralinTeam (Andersons, LebanonTurf, LESCO, Regal, UHS) Team Pro (Dow AgroSciences)BensulideBensumec 4LF, Pre-San 12.5G, 7G (PBI/Gordon) Squelch (Opti-Gro)Weedgrass Preventer (Andersons)BentazonBasagran T/O (BASF)Lescogran (LESCO)Nutgrass ‘Nihilator (Monterey)Bentazon + atrazinePrompt 5L (BASF)BromoxynilBuctril (Bayer)Cacodylic acidMontar, Weed Ender (Monterey)CarfentrazoneQuicksilver (FMC)Carfentrazone + 2,4-D + MCPP + dicambaSpeedZone, SpeedZone Southern (PBI/Gordon)Carfentrazone + MCPA + MCPP + dicambaPowerZone (PBI/Gordon)ChlorsulfuronCorsair (Riverdale)ClethodimEnvoy (Valent U.S.A.)ClopyralidLontrel T&O (Dow AgroSciences)CMA (CAMA)Selectrol (Opti-Gro)Corn glutenDynaweed (Soil Technologies)2,4-DAM-40, 2,4-D Granules, 2,4-D L. V. Ester, Solution (Riverdale)Gordon's Amine 400 (PBI/Gordon)Weedone LV4 (Bayer)2,4-D + clopyralid + dicambaMillennium Ultra (Andersons, Riverdale)2,4-D + clopyralid + dicamba + MSMAMillennium Ultra Plus (Riverdale)2,4-D + clopyralid + triclopyrMomentum (LESCO)2,4-D + dicamba81 Selective Weedkiller (Riverdale)Four Power Plus (UHS)2,4-D + dichlorprop2D + 2DP Amine, Turf D + DP (Riverdale)Fluid Broadleaf Weed Control (Andersons)2,4-D + dichlorprop + dicambaSuper Trimec, Brushmaster (PBI/Gordon)2,4-D + mecoprop (MCPP)2D Amine + 2 MCPP (Riverdale)2 Plus 2 (Syngenta)2,4-D + MCPP + dicambaBentgrass Selective Weed Killer, Three-Way Selective (LESCO)Broadleaf Trimec (LebanonTurf)MecAmine-D (UHS)Trimec Bentgrass Formula, Trimec Classic, Trimec-LAF 637, Trimec Southern, Trimec 992 (PBI/Gordon)Triplet Sensitive, Triplet Water Soluble (Riverdale)Weed-A-Cide (Opti-Gro)2,4-D + MCPP + dichlorpropBroadleaf Granular Herbicide (LESCO)Dissolve, Triamine, Triamine Jet-Spray (Riverdale)Turf Weeder (Howard Johnson’s)2,4-D + MCPP + MSMA + dicambaTrimec Plus (PBI/Gordon)2,4-D + triclopyrChaser, Chaser 2 Amine (UHS)Turflon II Amine (Riverdale)DCPA (Dacthal)Dacthal (Syngenta)DicambaKOG (Andersons)Oracle (Agrisel USA)Vanquish (Syngenta)DiclofopIlloxan (Bayer)DiquatAquatrim II (Opti-Gro)Reward (Syngenta)DithiopyrCrab & Spurge Preventer (Monterey)Dimension (Andersons, Best/Simplot, Dow AgroSciences Howard Johnson’s, LebanonTurf)Dimension 270-G (Best/Simplot)Dimension Ultra (Dow AgroSciences)Lifeguard (LESCO)DSMAMethar 30 (Cleary)EthofumesatePrograss (Bayer)FenarimolRubigan A.S. (Gowan)Patchwork (Riverdale)FenoxapropAcclaim Extra (Bayer)COMMON NAMETRADE NAMES (SUPPLIERS)1Fluazifop-P-butylFusilade II (Syngenta)Ornamec Over-The-Top, Ornamec 170 (PBI/Gordon)ForamsulfuronRevolver (Bayer)Glufosinate-ammoniumFinale (Bayer)GlyphosateAquaNeat, Razor (Riverdale)Clear-Out 41 Plus (Agrisel USA)Glystar Pro (Agrisel USA)GlyphoMate 41 (PBI/Gordon)Kleenup Pro (UHS)Prosecutor, Prosecutor Pro, Prosecutor + Tracker (LESCO)Roundup Pro, Roundup ProDry (Monsanto)Touchdown Pro (Syngenta)Trailblazer (Opti-Gro)Glyphosate+diquat dibromideProsecutor Swift Acting (LESCO)QuikPRO (Monsanto)HalosulfuronManage (Monsanto)ImazapicPlateau 70DG (BASF)ImazaquinImage 70DG (BASF)IsoxabenGallery (Dow AgroSciences)MCPAMCPA-4 Amine (Riverdale)MCPA + clopyralid + dichlorpropChaser Ultra (UHS)MCPA + MCPP + dicambaTrimec Encore (PBI/Gordon)Tri-Power Dry, Tri-Power Selective (Riverdale)MCPA + MCPP + dichlorpropTriamine II (Riverdale)MCPA + triclopyr + clopyralidBattleship (Helena)MCPA + triclopyr + dicambaClover Power, Spurge Power (Monterey)Cool Power, Horsepower (Riverdale)Eliminate, Three-Way Ester II (LESCO)MCPP (Mecoprop)Chem-weed (Opti-Gro)MCPP-4 Amine (Riverdale)MCPP-4K (UHS)Mecomec (PBI/Gordon) MetribuzinSencor 75 Turf Herbicide (Bayer)Metsulfuron methylBLADE (PBI/Gordon)Manor (Riverdale)MSMADaconate 6, Daconate Super (Syngenta)MSMA SG, 6.6L (LESCO)MSMA Turf (UHS)Multipurpose MSMA Herbicide (Agrisel USA)Summer Crabicide (LebanonTurf)Weed Hoe (Monterey)MSMA + cacodylic acidMoncide (Monterey)OryzalinOryzalin Pro (Agrisel USA)Surflan (United Phosphorus Ltd.)Surflan Coated Granules (UHS)Weed Stopper (Monterey)OxadiazonRonstar (Bayer)Oxadiazon + bensulideGoosegrass/Crabgrass Control (Andersons)Oxadiazon + prodiamineRegalStar G (Regal)Pelargonic acidQuik (Monterey)PendimethalinPendiflex 32 (Agrisel USA)Pendulum (BASF)PRE-M (LESCO)Corral, ProPendi (Andersons)ProdiamineBarricade (Syngenta)RegalKade (Regal) Stonewall (LESCO)PronamideKerb (Dow AgroSciences)QuincloracDrive 75DF (BASF)RimsulfuronTranXit (Griffin L.L.C.)S - MetolachlorPennant, Pennant Magnum (Syngenta)SethoxydimGrass Getter (Monterey)Vantage (Agrisel USA, BASF)SiduronTupersan (PBI/Gordon)Tupersan 3.5% (Andersons)Tupersan 4.6% (LebanonTurf)SimazinePrincep (Syngenta)Sim-Trol (Sipcam Agro)Wynstar (Regal)TriclopyrTurflon Ester (Dow AgroSciences, Monterey)Triclopyr + clopyralidConfront (Dow AgroSciences, LebanonTurf)Trifloxysulfuron sodiumMonument 75WG (Syngenta)
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# Flowables (F or L). Some active ingredients are insoluble
solids. These may be formulated as flowables in which finely ground active ingredients are mixed with a liquid, along with inert ingredients, to form a suspension.
Flowables are mixed with water for application and are similar to EC or wettable-powder formulations in ease of handling and use. They are used in the same types of pest-control operations for which you would use ECs.Advantages of using flowables:# Seldom clog nozzles# Easy to handle and apply.Disadvantages of using flowables:# Require moderate agitation# May leave a visible residue.# Invert emulsions. This mixture contains a water-soluble pesticide dispersed in an oil carrier. Invert emulsions
require a special kind of emulsifier that allows the pesticide to be mixed with a large volume of petroleum-based carrier, usually fuel oil. When applied, invert emulsions form large droplets that do not drift easily. Invert emulsions are most commonly used in vegetation control along rights-of-way where drift to susceptible non-target plants is a problem.DRY FORMULATIONS# Dusts (D). Most dust formulations are ready to use and contain a low percentage of active ingredient (usually
0.5 to 10 percent) plus a fine, dry, inert carrier made from talc, chalk, clay, nut hulls or volcanic ash. The size of individual dust particles varies. A few dust formulations are concentrates and contain a high percentage of active ingredient. You must mix these with dry inert carriers before you can apply them. You always use dusts in dry form, and they easily drift onto non-target areas. Agricultural applications sometimes
use dusts. In structures, applicators use dust formulations
in cracks and crevices and for spot treatments. Seed growers also use dusts widely in seed treatments. Plus, you often see dusts used to control lice, fleas and other parasites on pets and livestock. Advantages of using dusts:# Usually ready to use, with no mixing# Effective where drift from spray might cause damage# Require simple equipment# Effective in hard-to-reach indoor areas.Disadvantages of using dusts:# Easily drift off-target during application# Residue easily moves off-target by air movement or water# May irritate eyes, nose, throat and skin# Do not stick to surfaces as well as liquids#Difficult to get an even distribution of particles on surfaces.# Baits (B). A bait formulation is an active ingredient mixed with food or another pest-attractive substance. The bait either attracts the pests or is placed where the pests will find it. Pests die by eating the pesticide in the bait. The amount of active ingredient in most bait formulations
is quite low, usually less than 5 percent.Baits are used inside buildings to control ants, roaches, flies and other insects and for rodent control. Outdoors, you’ll see them used to control snails, slugs and some insects, such as mole crickets, but their main use is for control of vertebrate pests such as rodents, other mammals
and birds.Advantages of using baits:# Ready to use# Don’t need to cover entire area because the pest goes to the bait# Control pests that move in and out of an area.Disadvantages of using baits:# Can be attractive to children and pets# May kill domestic animals and non-target wildlife outdoors#Pest may prefer the crop or other food to the bait# Dead pests may cause odor problem# Other animals may be poisoned as a result of feeding on the poisoned pests.It is important to remove baits when the pesticide becomes
ineffective or they may serve as a food source for the target pest or other pests.# Granules (G). Granular formulations are similar to dust formulations except that granular particles are larger and heavier. The coarse particles are made from an absorptive material such as clay, corn cobs or walnut shells. The active ingredient either coats the outside of the granules or is absorbed into them. The amount of active ingredient is relatively low, usually ranging from 1 to 15 percent.You most often use granular pesticides to apply chemicals
to the soil to control weeds, nematodes and insects living in the soil. You also use granular formulations to control larval mosquitoes and other aquatic pests.
2004 # TURF & LANDSCAPE DIGEST 95
FUNGICIDE SOURCESCommon nameTrade names (suppliers)1AzoxystrobinHeritage (Syngenta)BoscalidEmerald (BASF)ChloronebChloroneb, Fungicide V (Andersons)Teremec SP (PBI/Gordon)Chloroneb + thiophanate-methylFungicide IX (Andersons)ChlorothalonilBravado (Monterey)Chlorostar (Regal)Concorde DF, Concorde SST (Agrisel USA, Griffin LLC)Daconil (Andersons)Daconil Weatherstik, Ultrex & ZN (Syngenta)Echo 720, 90 DF, Zn (Sipcam Agro)Manicure (LESCO)Turf Fungicide (Lebanon)Chlorothalonil + fenarimolTwoSome Flowable Fungicide (LESCO)Chlorothalonil + thiophanate-
methylConSyst (Regal)Spectro 90WDG (Cleary)Copper ammonium complexLiqui-cop (Monterey)Copper hydroxideKocide 2000 T/N/O (Griffin LLC)Cuprous oxideNordox (Monterey)CyproconazoleSentinel (Syngenta)EtridiazoleKoban (Andersons)Terrazole (Crompton Uniroyal)FenarimolRubigan (Gowan)Patchwork (Riverdale)FludioxonilMedallion (Syngenta)FlutolanilProStar (Bayer)Fosetyl-alMonterey Aliette (Monterey)Prodigy Signature (LESCO)Signature (Bayer)Iprodione18 Plus (LESCO)26019, 26GT (Bayer)Agrisel Iprodione Pro Z (Agrisel USA)Fungicide X (Andersons)Iprodione Pro 2SE (TopPro)ManebPentathlon (Agrisel USA, Griffin LLC)MancozebDithane T/O Rainshield, Fore Rainshield (Dow AgroSciences)Formec 80 (PBI/Gordon)Mancozeb (LESCO)Pentathlon DF, Pentathlon LF (Agrisel USA, Griffin LLC)Protect T/O (Cleary)Mancozeb + copper hydroxideJunction (Griffin LLC)Mancozeb + myclobutanil
Manhandle (LESCO)Mefenoxam (metalaxyl)2Mefenoxam 2 (Sipcam Agro)Pythium Control (Andersons)Subdue Maxx GR, 2X WSP (Syngenta)MyclobutanilEagle (Dow AgroSciences, Lebanon)Golden Eagle (Andersons)Common nameTrade names (suppliers)1PCNBEngage (United Horticultural Supply) Par Flo 4F, PCNB 10G, WSP, 75W (Amvac)PCNB (Lebanon)PCNB, Penstar, Flo (Andersons)Revere (LESCO)Terraclor, Turfcide (Crompton Uniroyal)PhosphitesAlude (Cleary)Magellan (Riverdale) Polyoxin-DEndorse (Cleary)Potassium bicarbonateArmicarb 100 (Helena)Kaligreen (Monterey)PropamocarbBanol (Bayer)Propamocarb + chlorothalonil
Banol C (United Horticultural Supply)PropiconazoleBanner Maxx, GL (Syngenta)Spectator (LESCO)PyraclostrobinInsignia (BASF)Quartenary ammonium compoundsPhysan 20 (Maril)RD-20 (Monterey)Thiophanate-methyl3336 (Cleary)Agrisel T-Methyl Pro 4.5L (Agrisel USA)Fungo Flo, 50 WSB, Systemic Fungicide (Andersons)SysTec 1998 (Regal)T-Methyl Pro 4.5F, 50WSB (TopPro)T-Storm 50 WSB, 4.5F (LESCO)Thiophanate-methyl + iprodioneFluid Fungicide (Andersons)Thiophanate-methyl + flutolanilSysStar (Regal)Thiophanate-methyl + mancozebDuosan WP, WSB (Andersons)ThiramDefiant (Agrisel USA, Taminco)Spotrete (Cleary)TriadimefonAccost (United Horticultural Supply)Bayleton (Andersons, Bayer, Lebanon)Bayleton Systemic Fungicide, Granular Turf Fungicide (LESCO)Fungicide VII (Andersons)Fungisol (Opti-Gro)Lawn Fungicide, Bayleton 1G (Howard Johnson’s)Triadimefon + metalaxylFluid Fungicide II (Andersons)Trichoderma harzianumTurfMate, Turfshield (BioWorks)TrifloxystrobinCompass (Bayer) VinclozolinCuralan (TopPro)Touché (LESCO)1 No endorsement of named products by the author or publisher is intended, nor is criticism implied for products not included in this table. Fertilizer/pesticide combinations are not included in this Update.2 Mefenoxam (metalaxyl-m) is an isomer of the traditional metalaxyl, formerly found in Subdue and other metalaxyl formulations.3 EPA registration pending as of press time.
96 TURF & LANDSCAPE DIGEST # 2004 chapter 12
INSECTICIDE SOURCES1AcephateAcephate Pro 75 (BASF)Agrisel Acephate Pro 75 (Agrisel USA)LESCO-Fate (LESCO)Orthene Turf, Tree and Ornamental (Valent U.S.A.)AzadirachtinAzatrol (PBI/Gordon)Ornazin (Amvac)ß-cyfluthrinTempo SC Ultra, Temp Ultra WP (Bayer)Bacillus thuringiensis aizawaiXenTari (Valent U.S.A.)Baccillus thuringiensis israelensisVectoBac (Valent U.S.A.)Bacillus thuringiensis kurstakiDiPel DF (Valent U.S.A.)Bacillus thuringiensis sphaericusVectoLex (Valent U.S.A.)BifenthrinCrosscheck (LESCO)Talstar (Andersons, FMC, LebanonTurf)Boric acidTriad Granular Bait (LESCO)CarbarylAgrisel Carbaryl 5 Granular, Agrisel Carbait 5 (Agrisel USA)Regal Fate (Regal)Sevin (Andersons, Bayer, LESCO, UHS)Sevin G (LebanonTurf)ChlorpyrifosChlorpyrifos Granules (Howard Johnson)Chlorpyrifos 2E T&O Insecticide (Agrisel USA) Dursban (Andersons, LESCO, Prentiss, UHS)Dursban 1% (Howard Johnson)Dursban 1% Granular Bait, Granular Insecticide (LESCO)Dursban 2 Coated Granules (UHS)Dursban Pro, Dursban 50W (Dow AgroSciences)Insecticide III (Andersons)CyfluthrinTempo (Bayer)CypermethrinCynoff (FMC)Demon TC (Syngenta)DeltamethrinDeltaGard (Bayer)Regal DeltaGard (Regal)DiazinonDiazinon (Howard Johnson, LESCO, Prentiss, UHS) EsfenvalerateSect-B-Gone (Opti-Gro)EthionEthion (FMC)Eugenol + 2-phenethyl propionateEnviro-Sect (Opti-Gro)FenamiphosNemacur (Bayer)FenoxycarbAward (Syngenta)FipronilCeasefire, Chipco Choice, Chipco TopChoice (Bayer)HalofenozideMACH 2 (Andersons, Dow AgroSciences, LebanonTurf)HexahydroxylEco Exempt G, Eco Exempt IC Insecticide Concentrate (Prentiss)HydramethylnonAmdro Pro (BASF)Siege (BASF)ImidaclopridImidacloprid (Andersons) Merit (Bayer, Howard Johnson, LESCO) Merit 0.3G (LebanonTurf)Lambda-cyhalothrinBattle GC (LESCO)Scimitar (Syngenta)MalathionMalathion (Agrisel USA, PBI/Gordon, Prentiss)MethopreneExtinguish (Wellmark)Myrothecium verrucariaDiTera-WDG, DiTera DF, DiTera ES (Valent U.S.A.)Permethrin10% Permethrin (BASF)Agrisel Multipurpose Insect Killer, Agrisel Multipurpose Insect Killer II, Agrisel Fire Ant Killer, Agrisel Permethrin Technical,
Agrisel Permethrin Pro, Agrisel Permethrin 360 Insecticide (Agrisel USA)Astro, Dragnet, Flee (FMC)Perm-X (Prentiss)Permethrin 3.2, 0.25% Granular (BASF)Prelude (Syngenta)PyrethrinExciter (Prentiss)Pyganic (Monterey)PyriproxyfenDistance Fire ant Bait (Valent U.S.A.)SpinosadConserve SC (Dow AgroSciences)Fire Ant Bait with Conserve (UHS)Steinernema scapterisciNematac S (Becker Underwood)Tau-fluvalinateMavrik Aquaflow (Wellmark)Mavrik Perimeter (Zoecon)TrichlorfonDylox (Andersons, Bayer)Grub Control with Dylox (LebanonTurf)Pronto White Grub Control (PBI/Gordon)Stop Grub (Howard Johnson)1 No endorsement of named products is intended by the publisher or author, nor is criticism implied by the omission of a product from this list.
2004 # TURF & LANDSCAPE DIGEST 97
Advantages of using granules:# Ready to use—no mixing# Drift hazards low, and particles settle quickly# Little hazard to applicator—no spray, little dust# Weight carries the formulation through foliage to soil or water target#Simple application equipment, such as seeders or fertilizer
spreaders# May break down more slowly than WPs or ECs through a slow-release coating.Disadvantages of using granules:# Does not stick to foliage or other non-level surface# May need to incorporate in soil or water# May need moisture to start pesticidal action# May be hazardous to non-target species, especially birds that mistakenly feed on the grain- or seed-like granules.# Wettable powders (WP or W). Wettable powders are dry, finely ground formulations that look like dusts. You typically must mix them with water for application as a spray. You can often apply products, however, either as a dust or as a wettable powder—the choice sometimes is left to the applicator. Wettable powders contain 5 to 95 percent active ingredients.
Wettable-powder particles do not dissolve in water. They settle out quickly unless you agitate them constantly to keep them suspended.Wettable powders are one of the most widely used pesticide formulations. You can use them for most pest problems and in most types of spray equipment where agitation is possible. Advantages of using wettable powders:# Easy to store, transport and handle# Less likely than ECs and other petroleum-based pesticides
to cause unwanted harm to treated plants and surfaces# Easy to measure and mix# Less skin and eye absorption than ECs and other liquid formulations.Disadvantages of using wettable powders:# Inhalation hazard to applicator while pouring and mixing the concentrated powder# Require good and constant agitation (usually mechanical)
in the spray tank and quickly settle out if agitation
is turned off# Abrasive to many pumps and nozzles, causing them to wear out quickly# Difficult to mix in hard or alkaline waterOFEATURES THAT IMPROVEOPERATOR SAFETYOperator safety is one of the biggest concerns facing the application industry today. Two features that aid in ensuring operator safety include direct-injection systems
and closed chemical-transfer systems. Both are designed to decrease your contact with the chemicals you’re applying.# Direct-injection systems limit your contact with chemicals by directly injecting the chemical into the fluid stream just before it reaches the nozzles. This eliminates your need to mix chemicals before you spray. The unit carries the chemicals in separate containers from the main tank. Thus, the main tank contains only clean water, and the injection-metering system ensures the unit uses only the exact amount of chemical needed. This type of system also eliminates leftover spray mix in the tank.Direct-injection systems cost more because they rely on individual metering pumps for each chemical used in addition to the main system pump. If you like the idea of direct-injection systems, check that the unit you consider has a mixing chamber. This feature ensures the water and chemical mix thoroughly before reaching the spray tip. If your unit has no mixing chamber,
the injection point should be located well ahead of the spray tips to allow sufficient time for self-mixing.
Improper mixing results in non-uniform chemical concentrations during your application.# Closed chemical-transfer systems are a less expensive
way to gain operator safety. A closed chemical-transfer system typically consists of a quick-connect coupler permanently mounted to a tank inlet with a mating coupler you can attach to chemical containers. This system creates a closed transfer of the chemicals, reducing the chance of spillage or operator contact. Look for a system with some type of flow-control device
built into the coupling system so you can control the amount of chemical you’re adding to the tank.Many companies provide chemicals in bulk containers that also use a closed chemical-transfer system. Check with chemical providers to determine if you need to use a special coupler with their bulk-container systems.Other features adding safety to the system include a shut-off valve at the tank outlet, operator cabs, cab-ventilation systems and a clean-water tank.
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# Often clog nozzles and screens# Residues may be visible.# Soluble powders (SP or WSP). Soluble-powder formulations
look like wettable powders. However, when you mix them with water, soluble powders dissolve readily
and form a true solution. After you thoroughly mix them, no additional agitation is necessary. The amount of active ingredient in soluble powders ranges from 15 to 95 percent; it usually is more than 50 percent. Soluble powders have all the advantages of wettable powders and none of the disadvantages except the inhalation hazard during mixing. Few active ingredients are soluble in water.# Microencapsulated pesticides (M). Microencapsulated
formulations are particles of pesticides (liquid or dry) surrounded by a plastic coating. You mix the formulated product with water and apply it as a spray. Once applied, the capsule slowly releases the pesticide. The encapsulation process can prolong the active life of the pesticide by providing a timed release of the active ingredient. Advantages of using microencapsulated pesticides:# Increased safety to applicator# Easy to mix, handle and apply# Releases pesticide over a period.Disadvantages of using microencapsulated pesticides:
# Constant agitation necessary in spray tank# Some bees may pick up the capsules and carry them back to their hive where the released pesticide may poison
the entire hive.# Water-dispersible granules (dry flowables) (WDG or DF). Water-dispersible granular formulations are like wettable-powder formulations, except the active ingredient
is prepared as granule-sized particles. You must mix water-dispersible granules with water to apply them. Once in water, the granules break apart into a fine powder.
The formulation requires constant agitation to keep it suspended in water. Water-dispersible granules share advantages of wettable powders except:Figure 2. Plumbing diagram using centrifugal pump and self-cleaning strainer.Boom-control valvesElectrical-regulating valveTo controller gaugeThrottling valveTank shut-offThrottling valveCentrifugal pumpLine strainerThrottling valveJetagitatorGauge teeBoom section 1Boom section 2Boom section 3Technical credit: Spraying Systems Co.
2004 # TURF & LANDSCAPE DIGEST 99
# They are more easily measured and mixed# They cause less inhalation hazard to the applicator during pouring and mixing.FUMIGANTSFumigants are pesticides that form poisonous gases when applied. Some active ingredients are liquids when packaged under high pressure but change to gases when they are released. Other active ingredients are volatile liquids when enclosed in an ordinary container and so are not formulated under pressure. Others are solids that release gases when under conditions of high humidity or in the presence of water vapor. For turf and ornamental
purposes, you use fumigants to control a broad range of pests (weeds, weed seed, insects and fungi) in the soil.Advantages of using fumigants:# Toxic to a wide range of pests# Can penetrate soil# Single treatment usually controls most pests in the treated area.Disadvantages of using fumigants:# In most cases, the target site must be enclosed or covered to prevent the gas from escaping # Highly toxic to humans and all other living organisms
# Require the use of specialized protective equipment, including respirators# Require the use of specialized application equipment.
GELSAs the word suggests, pesticides formulated as gels are in a semi-solid, gelatinous state. Manufacturers generally
package gels in water-soluble bags or packets, allowing
operators to easily and cleanly handle, mix and load the pesticide. This reduces hazards to the operator and container-disposal problems. A disadvantage of gels, as with any pre-measured packaging, is that this limits you to using only the incremental
amounts contained in each package. However, gels’ ease of use means you’ll probably see more products formulated this way in the future.ADJUVANTSAn adjuvant is a chemical you add to a pesticide formulation
or tank mix to increase its effectiveness or safety. Most pesticide formulations contain at least a small percentage of adjuvants. Some of the most common adjuvants are surfactants—surface-active ingredients that alter the dispersing, spreading and wetting properties of spray droplets.Some examples of common adjuvants are:• Wetting agents: Allow wettable powders to mix with water
• Emulsifiers: Allow petroleum-based pesticides (ECs) to mix with water• Invert emulsifiers: Allow water-based pesticides to mix with petroleum-based carriers• Spreaders: Allow pesticide to form a uniform coating layer over the treated surface• Stickers: Allow pesticide to stay on the treated surface• Penetrants: Allow the pesticide to get through the outer surface to the inside of the treated area• Foaming agents: Reduce drift• Thickeners: Reduce drift by increasing droplet size• Safeners: Reduce the toxicity of a pesticide formulation to the pesticide handler or the treated plant• Compatibility agents: Aid in combining pesticides (and fertilizers) effectively• Buffers: Allow pesticides to be mixed with diluents or other pesticides of different acidity or alkalinity• Anti-foaming agents: Reduce foaming of spray mixes that require vigorous agitation. CALCULATING AND CALIBRATING PESTICIDESSee the Appendix: Turf and landscape calculations for information on calculating the best buy, determining how much to add to a tank and calibrating sprayers and spreaders.SPRAY EQUIPMENTChoosing the proper spraying equipment can make pesticide application either a simple or a difficult task. The following set of guidelines will help you decide which sprayer features best match your needs. As you make your decisions, keep in mind your or your operator’s
skill level in using the equipment. Some sprayers require additional training depending on the features you select.When considering the purchase of spray equipment, several variables are important. You need to look at tank aspects, pumps, pump capacity, agitation method, strainers
and filters, booms, nozzle bodies, sprayer monitors and controls, nozzle monitors, pressure gauges and safety aspects. Let’s consider each here.SPRAY-TANK ASPECTSYour first consideration when purchasing spray equipment
is determining the size tank you need, as well as what materials you prefer for its construction. Common
tank-construction materials include fiberglass, molded plastic and stainless steel. Most importantly, the tank material should be corrosion-resistant and compatible with the chemicals you apply.
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To ensure ease in cleaning, look for a tank design that minimizes leftover spray mix in the bottom. This will help you avoid disposal problems. Some tanks have a built-in sump that helps empty them completely.
Also look for a drain plug at the tank’s lowest point to ease cleaning.Finally, the liquid level in the tank should be clearly marked, or the tank should have a sight gauge (visible from your seated position) that shows levels.
CHOOSING A PUMPThe pump on your sprayer must deliver adequate flow and pressure for all applications. It also should handle the desired chemicals with minimal corrosion and wear. Pumps generally fall into two categories: positive-displacement
pumps and non-positive-displacement pumps. Positive-displacement pumps include roller pumps, diaphragm
pumps and piston pumps. Non-positive pumps include centrifugal pumps (see Figure 2, page 98).# Roller pumps produce moderate flows and pressures. A slotted rotor, revolving in an eccentric case, holds the rollers. As the rollers pass the pump inlet, the cavities between and under them enlarge and draw in liquid. When nearing the outlet, the cavities contract—due to the eccentric housing—and force the liquid out of the pump.Roller pumps handle a variety of pesticides and have low initial and maintenance costs. These pumps operate efficiently but, as pressure increases, their volume (output)
decreases. If you primarily use wettable powders, a roller pump probably isn’t your best choice. Roller pumps are not well-suited to abrasive materials because they rapidly wear the pump housing, the rotor slots and the rollers. Replacing the rollers is easy but—depending on housing wear—may not restore the pump to its previously
satisfactory working condition. Roller pumps with nylon rollers work well with most chemicals, but rubber rollers are slightly better if you must use abrasive materials
with these units.# Centrifugal pumps create flow and pressure from an impeller’s
centrifugal force. Liquid enters through the impeller’s
center. As it spins, centrifugal force throws the liquid into a spiral passage leading to the outlet. The only moving parts in a centrifugal pump are the shafts and impellers. The impellers operate at a high rpm to give rated performance.
PTO-powered centrifugal pumps require speed-up drives and high engine rpms, which can waste fuel when spraying. An alternative is a pump powered by a hydraulic motor connected to the sprayers’ hydraulic
system. Centrifugal pumps last a long time—even with wettable
powders—and produce a high flow volume that is ideal for hydraulic agitation in the sprayer tank.# Diaphragm pumps have at least one chamber sealed at one end by a membrane or diaphragm. The other end has an inlet and outlet valve. The diaphragm connects to a piston.
As the piston moves, suction draws the liquid through the inlet valve by moving the diaphragm, which enlarges the chamber. The piston’s return forces the diaphragm
inward, shrinking the chamber and propelling the liquid out. A compression chamber smoothes line pulses. Ask to add one if it isn’t already incorporated into the design of a pump you like.Diaphragm pumps require minimal maintenance because
less contact takes place between the spray material and moving parts. Nevertheless, you’ll need to periodically
check the diaphragm for pinhole leaks that can cause problems and lower pressure. Ask whether the diaphragm pump you are considering will resist the chemicals you use. Abrasive materials are less likely to damage this type of pump.# Piston pumps propel liquid by a piston moving in a cylinder,
similar to a combustion engine. The intake stroke draws the liquid in through one valve, and the output stroke forces the liquid through another valve. Piston pumps have either an internal or external air chamber (surge tank) to dampen pulsations in the liquid flow associated with each stroke. Without a surge tank, the spray will pulse rather than being applied in a steady flow. Piston pumps develop high pressures, which can increase
a sprayer’s versatility. However, the relative capacity
of piston pumps is often low. Because higher-volume piston pumps are expensive, they normally use mechanical
agitation instead of hydraulic agitation. As a professional applicator, look for larger-capacity pumps driven by an auxiliary engine. The large pumps—with 2 to 8 cylinders—achieve higher flow rates, and the multi-cylinder design produces more even flow.THE IMPORTANCE OF PUMP CAPACITYLook for a sprayer with a large enough pump to handle your capacity requirements. Due to mechanical inefficiencies,
some pumps don’t pump at appropriate pressures to move sprayer chemicals. Thus, make sure you choose a pump with a capacity that is 50 to 75 percent higher than your calculated flow requirements. The pump should have sufficient capacity to supply several nozzles, provide hydraulic agitation (if used), return flow for self-cleaning strainers and bypass-type regulating valves, and offset pump wear. HOW AGITATION AFFECTSCHEMICAL APPLICATIONThe type of agitation you choose depends on the chemical formulations you apply. A uniform chemical
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application depends on a uniform tank mix. If the chemical separates from its carrier, you’ll apply unequal
chemical concentrations. Therefore, all sprayers benefit from a tank agitator to maintain a uniform mix.Two common types of agitation are hydraulic agitation and mechanical agitation.# Hydraulic agitation, commonly called jet agitation, uses part of the pump’s flow to create a mixing action in the tank. With this type of system, you need a pump large enough to provide the extra flow volume that the jet agitator requires. Typically, you can use 5 to 10 percent of tank volume to determine the necessary flow. The flow can be through a standard agitation nozzle or a specially designed siphon nozzle. The siphon agitation nozzle creates
a venturi effect—or vacuum—that increases the nozzle’s discharge. This increases the mixing action by two-and-a-half times and is effective when the available flow is marginal. Hydraulic agitation also can consist of a sparger—a pipe or tube with several discharge holes—in the tank’s bottom. Check that the hydraulic agitator is in the bottom of the tank so it sweeps all areas.Units with hydraulic agitation also should have some type of flow-control device. Too much agitation creates foaming in the tank, while not enough creates unequal chemical concentrations. A flow-control valve in the agitation line allows you to adjust the flow for a given chemical mix.# Mechanical agitation is produced by paddles or propellers on the tank’s bottom. The sprayer’s power source or a 12-V electrical motor drives these mixers. Sprayers with piston pumps typically use mechanical agitators, because jet agitation requires a larger flow, which results in a more expensive piston pump. Any of these agitators, when properly designed and operated, will adequately agitate most pesticides. STRAINERS AND FILTERSLine strainers are an important part of the sprayer’s plumbing system. A properly placed and sized strainer can prevent your worst nightmare: plugged nozzles. Strainers come with different mesh sizes, which indicate the number of screen openings per linear inch. For example,
strainers with mesh sizes of 100 and 200 have smaller openings than mesh sizes of 30 or 50.For most positive-displacement pumps, you need a suction-line strainer—with a mesh size of 30 or 50—between the tank and pump. This type of strainer protects these pumps’ small, internal, moving parts.On a centrifugal pump, you must ensure that the pump’s inlet is not restricted. Thus, look for a line strainer on the pressure side of the centrifugal pump. The strainer should have a 50-mesh screen. In this location, it will protect both the nozzles and the agitation system. Using a suction-line strainer, as suggested for positive-displacement pumps, could cause problems on a centrifugal
pump because it could plug, which could cause pump cavitation. Pump cavitation causes premature pump wear, leading you to need a new pump sooner rather than later.A feature that you’ll sometimes find on both non-positive- and positive-displacement pumps is a self-cleaning
line strainer. This type of strainer directs a high-velocity
flow past the screen face, which continuously washes particles into a separate, unrestricted bypass line. Typically, you need a system with 6 to 8 gpm through the bypass line for proper operation.Some sprayer manufacturers also put a small line strainer—with a 100- or 200-mesh screen—on each boom section. These strainers reduce your need to clean nozzle-tip strainers by catching small particles that larger strainers did not catch.Nozzle-tip strainers also are important. They are your last line of defense against nozzle plugging. These strainers come in an assortment of sizes and materials. The nozzle’s orifice size dictates the necessity for and the mesh size of a nozzle-tip strainer. See your nozzle manufacturer’s catalog for recommendations. THE BENEFIT OF BOOM-CONTROL VALVESSometimes you need to spray an area that’s narrower than your boom’s full width. As a result, manufacturers offer booms divided into several sections with individual
valves. These valves are either manual or electrical and control the flow to either the left, center or right boom section, or any combination.Many of these turf sprayers have remote-control, solenoid-
operated valves. These typically have about a 10-gpm capacity with a 5-psi pressure drop and about a 100-psi maximum. These systems are relatively inexpensive and, with proper maintenance, can give years of service.More turf sprayers today offer remote-control-operated,
motorized ball valves. Having larger passages, these valves typically have higher flow rates and higher maximum operating pressures than solenoid valves. Ball valves can be slightly more expensive than solenoid valves. However,
they tend to be less maintenance-intensive in the long run.Other sprayers use three-way valves. Available in both solenoid- and ball-valve-type, these units allow the system
to maintain constant pressure when any boom sections
are shut off. This places less strain on the sprayer system by reducing pressure spikes. A three-way valve system is a good feature if you constantly turn booms on and off. Some sprayer manufacturers have turned to installing
manifold-type control-valve systems on their sprayers.
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chapter 12These make maintenance and repair of the valves easier by allowing you to replace or repair one without completely disassembling the hoses or pipes.BOOM OPTIONSBooms are available in two basic types: wet and dry. A wet boom is one in which the fluid travels through the boom itself. Dry booms are those that use hoses to supply fluid from one nozzle body to the next. A boom-support member typically supports the nozzle bodies.Choosing a unit with a sturdy boom made from strong corrosion-resistant material is a good place to start. However some booms have the following extra conveniences you may want to consider: # Automatic boom-height control. This type of unit uses sonar to monitor the distance from the boom to the ground. As the terrain changes, the boom adjusts automatically with actuators on each boom to maintain a constant application height. This is an important feature to consider because boom height is so important
to maintaining good spray distribution.# Remote-control boom fold-up. This feature allows you to fold the booms without dismounting the sprayer. It is useful if you must drive your sprayer around many obstacles. # Shielded booms are becoming more popular due to the demand for better drift control. Shielded or hooded sprayer enclose the nozzle bodies or the entire boom section. These enclosures prevent the wind from carrying
the small drops off target. This feature is great for drift control, but it may require the use of a nozzle monitor to inform you of a clogged nozzle because you won’t be able to see if they are working properly.
DIFFERENCES IN NOZZLE BODIESNozzle bodies come in many shapes and sizes. As with boom types, they are available for both wet or dry booms, with or without diaphragm check valves and with multiple- or single-nozzle outlets.# Diaphragm-check-valve nozzle bodies are a plus because they prevent nozzle dripping after you shut off the booms. This prevents chemical contamination on areas outside the spray zone.# Multiple-nozzle or turret-type nozzle bodies give you greater
flexibility when it comes to changing spray tips or unclogging them. All you need is to index the turret to the next nozzle and resume spraying with minimal downtime.MONITORING AND CONTROLLINGSprayer-system monitors continuously sense the sprayer’s operation, measuring travel speed, pressure and flow. Using this information, the device calculates the application rate and other useful information, such as application swath width and gallons of spray mix in the tank. You can use this information to better control the spraying operation, resulting in more precise pesticide application and better pest control. Most monitors today come with an automatic rate-control function. This controller calculates the actual application rate and constantly compares it to a pre-set desired rate. If the controller detects a discrepancy (error), it automatically adjusts the application rate (usually by adjusting flow). Some controllers have pre-set alarms that alert you if the error is too large to correct. These types of errors include speed varying too much for pressure compensation, hose or connection
breaks, line-strainer plugs or other serious problems.
A NEW OPTION: NOZZLE MONITORSSome new sprayers have monitors that sense flow at individual nozzles. When nozzle flow stops, due to plugging or a loss of pressure, a signal—such as a flashing light or a buzzer—alerts you. This helps you detect clogged nozzles you can’t see from your driver’s seat or nozzles located under hooded or shielded booms.THE PRESENCE OF PRESSURE GAUGESLook for a unit with a pressure gauge designed to measure liquid pressure in a range of about one-and-a-half to two times the maximum anticipated pressure. Another beneficial sprayer feature is a dampener between
the gauge and the sprayer to smooth pressure pulsations. This makes the gauge easier to read and prolongs the life of moving parts. Liquid-filled gauges
are preferable to dry gauges because the liquid dampens needle vibrations. If you’ve now detailed the specific features you want your sprayer to have, you probably are ready to shop. Keep in mind that you may not find the perfect sprayer with all of the features described here. Nevertheless,
you’re bound to find several that meet most of your requirements. At the very least, you know all the advantages and disadvantages of the various features,
which can help you better balance which sprayer will be appropriate for your needs.
Weed Identification & Management
One researcher estimates that weed management, worldwide, occupies more human time and effort than any other single activity. Certainly it is a major aspect of the management of any turf or landscape site. The first step in controlling weeds is to know the species
with which you are dealing. Weed identification can be tricky, considering the huge number of weed species that exist and the similarity of many closely related types. However, by learning the major weed species, you will be able to recognize most of the weeds you’ll see in landscapes.IDENTIFYING WEEDSMost weeds in turf and landscapes fall into two major groups. The first we call broadleaf weeds, or, as scientists refer to them, dicots. The second major group is the monocots, which includes the grasses. However, other monocots can pose problems for the landscape manager. Sedges, which many mistakenly believe to be grasses (hence the misnomer “nutgrass”), are common weed pests. Algae and mosses, which are neither monocots nor dicots, can be difficult to eradicate as well. It is important to know how to tell these groups apart because the success or failure of control measures depends on using the right product. For example, broadleaf herbicides
usually do not affect grasses and vice versa. And while most of us intuitively recognize a grass plant when we see it, you’ll run into situations where it is difficult to tell.Once you have decided which major group to which a weed belongs, identifying particular species can become
more difficult because related species often appear quite similar. The most convenient identification system is one that uses photos or drawings. However, picture-identification manuals can only include a limited number of species, and this is their main drawback. Even so, good picture manuals cover most of the weeds you’ll encounter
and are the kind on which most turf-and-ornamental professionals rely.More exhaustive manuals use keys that rely on anatomical
characteristics. These are typically more comprehensive
but also are more difficult to use and may require some expertise. Extension weed specialists are excellent resources when you have trouble identifying a weed species.LIFE CYCLEAnother way to group weeds is by their life cycle. As with ornamentals, some weeds are perennial and live for many years. Others complete their life cycle in just 1 or 2 years—these are annuals and biennials, respectively. Weed-control strategies heavily depend on whether a weed is perennial or annual. Any good identification manual provides this kind of information.If you do not know the identity of a weed, you often can still determine whether it is perennial. Perennials possess underground, permanent structures that annuals do not. Locating these indicates that the weed is indeed perennial. Look for rhizomes, bulbs, tubers or large, fleshy roots. However, young perennials often are difficult
to tell apart from annuals because they have not yet developed these structures.Germination time is another aspect of weed biology that affects control measures, especially timing. Summer annuals almost always germinate in spring or early summer.
Winter annuals and many biennials germinate in late summer or fall. Perennials can germinate almost any time, depending on the species, but do so predominantly in spring and fall. Obviously, you must apply pre-emergence
controls before germination takes place, so this information has great practical impact.MAJOR WEED GROUPS# Broadleaf weeds (dicots). As the name implies, these usually have relatively wide leaf blades compared to grasses, whose leaves tend to be long, narrow and pointed. However, it is difficult to generalize by this because broadleaf weeds display such a wide variety of leaf shapes and sizes. The key characteristic is leaf venation (see Figure 1, at left). Grasses (and other DICOTSPinnate venationPalmate venationMONOCOTSParallel venationFigure 1. Leaf-venation patterns.
104 TURF & LANDSCAPE DIGEST # 2004 chapter 13monocots, such as sedges) have parallel venation, meaning that all of the veins in their leaves run parallel to one another. Broadleaf plants possess either palmate or pinnate venation. Venation usually is an accurate way to distinguish a broadleaf weed from a monocot.Leaves also are defined as either simple or compound (see Figure 2, left). Simple leaves possess one intact leaf blade, while compound leaves have multiple leaflets. This can be an important identification characteristic
for broadleaf weeds. A leaf type shared by several common weeds—for example, clover and many other legumes, poison ivy and Oxalis—is the trifoliate pattern.
Trifoliate leaves possess three leaflets (again, see Figure 2).A large number of herbicide products are available for broadleaf control. Broadleaf
weeds may be either perennial or annual, and both types are susceptible to these products, although perennials often require repeat treatments. In turf, selective
post-emergence broadleaf-weed treatments are routine and ordinarily quite effective. In ornamentals, most of which also are broad-leaved, selective control is difficult, and you must rely on other approaches.# Monocots. If you determine you have a monocot, the next step is to decide whether it’s a grass or a sedge (or something
else). Remember: “Sedges have edges.” Sedge stems are three-sided with sharp angles. You can easily feel this with your fingers by grasping the plant stem. In addition, sedge leaves arise from all three sides of the stem. Once you become familiar with the appearance of sedges, you’ll have little difficulty spotting them in the future.If the weed is not a sedge, it’s probably a grass. Grass leaves arise from just two sides of the stem, which is not triangular like sedges. Other common monocot weeds that are neither grasses or sedges include wild garlic, horsetails and rushes—all noted for having round, hollow leaves.Selectively controlling perennial grassy weeds in turf with post-emergence treatments is not as easy as controlling
broadleaf weeds. Much depends on the weed and the type of turf. In some instances, treatment is simple—in others, no good selective control exists.Pre-emergents are probably the best option for annual grassy weeds, but post-emergence controls are available for many species. Grassy weeds in ornamentals often are relatively easy to control with selective herbicides.• Sedges. Only a few sedge species are weedy in the United States, but they can be serious problems when conditions favor them. Only a limited number of products perform well on sedges, but they tend to be highly selective and work effectively in turf and, when registrations permit it, in ornamental plantings as well.• Woody perennials. Woody perennials, often simply referred to as “brushy” species on labels, present significant problems in rights-of-way, fence lines and other non-crop areas. The most common examples are young trees and vines such as grape, honeysuckle or poison ivy. Along fence lines that border turf areas, trees and vines sprout and can grow with physical protection from close mowing,
which otherwise would effectively control these plants.Herbicide products formulated specifically for treating woody plants post-emergently in non-crop sites are available.
However, the best approach, when possible, is to use a long-residual soil herbicide that will keep all weeds from becoming established on the site. Mulch also reduces
fence-line weed problems.LIFE HABIT AND CONTROL STRATEGY# Annuals. Annuals live no longer than the current season,
and pre-emergents are the best way to control them. By preventing seeds from germinating, you effectively eliminate the weed problem. If you already have an infestation,
you can be confident that once the current generation
has passed, pre-emergence herbicides will prevent further encroachment.The point is not that you should simply wait for the weeds to die off—if you must eliminate an existing annual-
weed infestation, products exist for this purpose. Rather, take the view that prevention—with pre-emergence
herbicides and cultural controls—makes the most sense. Because, for practical purposes, there is no end to the weed seeds waiting to germinate, many grounds-care professionals use pre-emergence herbicides regularly. Turf managers caring for high-quality turf often consider
this a “must.”# Perennials. Perennial weeds present a somewhat different
problem. It certainly is true that pre-emergents are an important part of controlling perennial weeds. However, if you inherit an existing perennial-weed problem, you must have some means of eliminating them—as perennials, they will not die off at the end of the season. Further, no pre-emergence control is perfect, and a few weeds always manage to break through. This is not a large problem with annuals but creates a situation SimpleTrifoliate (compound)Pinnately compoundPalmately compoundFigure 2. Simple and compound leaves.
2004 # TURF & LANDSCAPE DIGEST 105
you must correct if the weeds are perennial. Fortunately, numerous options exist for removing most perennial broadleaf weeds and some perennial grasses from turf.# Seedlings. Control measures are most effective when taken against younger weeds. Thus, it is advantageous to be able to identify seedlings in many cases. Entire manuals
have been written covering seedling identification, and these are useful to have on hand because the first leaves of seedlings—the seed leaves, or cotyledons—look very different from the plant’s subsequent leaves. However,
by being observant you soon will learn the species to which a seedling belongs. The first true leaves appear quickly, and these usually resemble the typical form of the plant.HERBICIDESHerbicides are grouped as systemic or contact, pre-emergence or post-emergence, and selective or non-selective.
Each type is suitable for some uses and not for others, depending on the site and the type of weed. For example, a non-selective herbicide is not suitable for use on desirable turf or ornamentals, except perhaps for directed spot spraying in beds. Contact herbicides are ineffective against perennial weeds, which require systemic
products. Pre-emergents are not useful against established weeds. For more information on pesticides, see Chapter 12.Once you identify a weed, you must find a product registered to control it. References are available that cross-reference according to species controlled, and many suppliers provide similar guides. Extension agents also make control recommendations, and chemical suppliers should have staff members with such expertise.Once you have identified products that provide control, you can narrow your choices according to site and crop registrations, cost, availability, preferred formulation and other factors. TIMING HERBICIDE APPLICATIONSTiming of applications depends on numerous factors: Pre-emergence herbicides. Obviously, these need to be present in the soil before the target weed seeds begin to germinate. Turf managers often try to apply pre-emergents
close to germination dates, believing this gives herbicides maximum potency when the seeds began to germinate. However, recent research suggests that many pre-emergence herbicides are effective in the spring even when applied the previous fall. Therefore, application windows for many products may be wider than previously
thought.Your particular weed problem should dictate the actual
time of application, which must precede weed-seed germination. Generally, you must treat for spring- and summer-germinating weeds in early spring or the previous
fall. Many perennials and biennials, as well as winter
annuals, germinate in the fall as well as spring. You should apply pre-emergents in late summer or early fall to control these weeds. Post-emergence herbicides. Because these products control weeds after they’ve started growth, germination times are not so relevant for post-emergence treatments. However, some products require cool-weather conditions to avoid injuring desirable turf and ornamentals, so spring or fall are the preferred application times. In addition, the age and physiological status of the weeds also affects herbicide activity, especially systemic products. Product labels indicate the best application times.CULTURAL CONTROLThe No. 1 rule for cultural weed control in turf is to maintain a dense, vigorous stand. Dense turf effectively competes against most weeds. Aside from this, it is beneficial
to correct soil problems that promote the growth of certain weeds. For example, dry, compacted soil tends to favor certain weeds such as knotweed. Low, wet areas promote the growth of moisture-loving weeds such as nutsedge. Correcting these conditions reduces these weed problems. Areas that are thin or bare from disease are quickly filled in by weeds.In ornamental beds, a thick mulch is probably the best method of reducing weeds. Organic mulches, such as wood products, are most popular, but landscape fabrics are effective as well. As with turf, dense ground cover out-competes most weeds.WEED IDENTIFICATION GUIDEThe following illustrations and descriptions show common,
problematic weeds in turf and landscape sites in most parts of the United States. You will encounter other weeds, of course, and a reference specific to your region may be helpful. Leaf characteristics noted in the following descriptions are illustrated in Figures 1 and 2.GRASSESField sandbur—Cenchrus incertusThis summer annual (sometimes biennial) is noted for its painful, spiny burs. It thrives in sandy soils and turf areas in the South. A few related species also can be problems,
and all possess irritating burs.
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Bermudagrass—Cynodon dactylonBermudagrass is a commonly
used turfgrass but becomes a tenacious weed in non-turf areas. Further, it has a tendency to invade other turfgrasses and is difficult
to control when it does so. It is perennial and spreads aggressively by way of stolons and rhizomes. Bermudagrass exists in most of the states but thrives best in warm climates.Smooth crabgrass—Digitaria ischaemum and large crabgrass—
D. sanguinalisThese two species may be responsible
for more pre-emergence
applications than any other weed. While smooth crabgrass
is somewhat more upright growing, they both appear similar
in mowed turf, an environment
where they are highly competitive. Both species can spread with stems that root at the nodes. These summer
annuals occur throughout most of the United States, and seeds germinate all summer, making them two of the most significant turf weeds.Goosegrass—Eleusine indicaThis summer annual is common
in both turf and non-turf areas and sometimes is confused
with crabgrass. It germinates
a bit later than crabgrass and grows in distinct tufts with silvery or white stems. Goosegrass grows throughout most of the United States.Nimblewill—Muhlenbergia schreberiThis is a perennial species with a spreading habit that makes it a troublesome
weed in cool-season turf. Mainly a weed of the Eastern United States, nimblewill prefers damp, cool sites.Annual bluegrass—Poa annuaAnnual bluegrass, which actually can be perennial or annual, enjoys cool temperatures. Thus, it may grow as a winter annual in warmer regions. It is an unattractive weed in dormant warm-season turf but also invades
cool-season turf, where its apple-green color contrasts with the generally darker-green desirable turfgrasses. Its seed heads, which annual bluegrass is able to produce even at golf-green height, are conspicuous. Perennial forms invade golf greens and slowly outcompete the bentgrass, until the putting surface is actually more annual
bluegrass than bentgrass in many cases.Green foxtail—Setaria viridisThis annual weed and two similar species (giant
and yellow foxtail) range over the entire continental United States. They do not usually present a serious problem in dense turf. However,
seedling turf and non-turf sites can be subject to serious infestations.Johnsongrass—Sorghum halapenseMore a weed of open ground than turf, this perennial grass forms large colonies with its creeping underground
rhizomes. It is a large plant, up to 5 or 6 feet tall, and requires aggressive treatment to eradicate it from a site.OTHER MONOCOTSYellow nutsedge—Cyperus esculentus and purple nutsedge—C. rotundusThese perennial species resemble
grasses but are members of a different family—the sedges. Grasping their distinctly triangular stems is a good method to confirm you’ve got a sedge. Both species enjoy warmth and ample moisture, so they are active during the summer.
Yellow nutsedge is common
throughout most of the country, but purple nutsedge is a weed mainly in the Southeast and far West. Yellow nutsedge, pictured, possesses tubers (“nuts”) at the end of rhizomes and produces yellow seedheads, while purple-nutsedge plants grow in chains or series along rhizomes and produce purple seedheads. It is important to be able to distinguish between the species, because some herbicides affect one but not the other.
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Cattails—Typha latifoliaCattails are monocots but not grasses. Clearly preferring wet areas, this weed spreads aggressively with perennial rhizomes.
It becomes large, up to 7 or 8 feet tall, and can form thick colonies in ditches,
ponds and low wet areas. Several species
are weedy, but this one is the most widespread and common.BROADLEAF WEEDSTumble pigweed—Amaranthus albusThis summer annual often is a problem
on newly established sites, including
turf. This species and another—
redroot pigweed—grow upright, while prostrate pigweed is a mat-forming plant. All three are widespread in the United States.Giant ragweed—Ambrosia trifidaThis large, upright summer annual is a common weed in open areas and newly established sites. It is well known as a cause of allergies. Two related species—common and western ragweed—also are common weeds.Shepherdspurse—Capsella bursa-pastorisThis winter annual is present in all regions
and may inhabit almost any site. It is not generally a serious pest in turf but can be a problem in newly seeded grass. A member of the mustard family, these weeds go by familiar names such as cress, rocket, pepperweed, mustard and radish. This group includes both perennials and annuals, and many (but not all) prefer cool weather. Thus, the mustard family includes many winter and spring annuals and perennials that grow in cooler parts of the year.Mouseear chickweed—Cerastium vulgatumThis herbaceous perennial is a widespread weed in lawns and other landscape sites. Its low growth habit allows it to thrive in closely cut turf. Though it resembles common chickweed—
an annual—its hairy leaves make it easy to distinguish.
Lambsquarters—Chenopodium albumThis tall, upright grower is a summer annual that mostly inhabits beds and other open areas. It can, however, compete with seedling
turf. It occurs throughout the United States.Chicory—Cichorium intybusChicory is a familiar site along roadsides and other low-maintenance, mowed sites. Even though chicory is an upright perennial,
it apparently tolerates mowing easily. Its brilliant blue flowers are distinctive.
Canada thistle—Cirsium arvenseCanada thistle is a common and serious weed problem on roadsides and in other open areas. It is perennial and can form large colonies with underground spread. Several other thistle species are weedy pests throughout the United States, though not all are perennial. The spiny leaves of thistle can be painful, so this weed deserves prompt attention whenever
it springs up in landscapes.Field bindweed—Convolvulus arvensisThis perennial vine is a challenge to control. Thriving equally well in turf, rambling over ornamental shrubs or twining along fence lines, this weed dies back to a deep rootstock
each winter. If this rootstock is not completely killed—no easy task—the vine will regrow. A member
of the morning-glory family, its white flowers are quite showy. Related
species include ornamental vines and several other weedy types.Horseweed—Conyza canadensisThis summer annual is mostly a weed of open places, though it can persist occasionally in low-maintenance turf. Horseweed can reach 6 or 7 feet in height on a narrow stem and so is a conspicuous weed. In turf, it is mowed short but may persist as a low tuft. Horseweed is common throughout the United States.Prostrate spurge—Euphorbia supinaProstrate spurge is a common summer annual in the
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Eastern half of the United States and along the West Coast. Not only does it invade turf—especially in thinned spots—it also is a persistent problem in beds. It forms mats starting in late spring, and seeds continue to germinate throughout the summer. Its milky sap aids identification.Ground ivy—Glechoma hederaceaGround ivy is a creeping herbaceous per-ennial that thrives in cool weather. Inhabiting the Eastern half of the United States, ground ivy grows in many situations. However, it presents a difficult problem
when it invades cool-season turf, which it out-competes
in moist, shady sites with its aggressive spread and tolerance of low mowing. Its extensive roots and rhizomes
make it difficult to control.Prickly lettuce—Lactuca serriolaThis winter annual or biennial occurs throughout the United States, but more commonly in Northern areas. An upright
grower, it persists in many urban and landscape settings, though it is not a serious turf pest. Henbit—Lamium amplexicauleHenbit is more common in the Eastern
United States but ranges elsewhere.
Preferring cooler weather, it typically grows as a winter or spring annual and can be a conspicuous weed in dormant warm-season turf. It germinates in fall and early spring.Common mallow—Malva neglectaMallow is widespread and common
in the United States, preferring
cooler regions but growing as a winter or spring annual in hot-climate regions. More of a weed in open spaces, it is a substantial problem on newly established sites.Black medic—Medicago lupulinaThis member of the legume family varies from annual to biennial to perennial. Growing in all regions of the United States, the weed resembles
white clover but has distinctive yellow flowers. A closely related species, bur clover, has prickly, irritating fruits. This plant has trifoliate leaves.Carpetweed—Mollugo verticillataCarpetweed is low-growing and germinates relatively late in the spring. However,
it establishes quickly in many sites, including turf and ornamental beds. The leaves are small and narrow, and the plant may form a thin mat.Yellow woodsorrel—Oxalis strictaYellow woodsorrel is a common turf and landscape
weed found throughout the United States. It is perennial with a low growth habit, allowing it to survive mowing in turf. Creeping
woodsorrel is a similar species that spreads somewhat more aggressively. Both species resemble clover superficially because of their trifoliate leaves, but woodsorrel flowers are yellow and not similar to clover flowers.Plantain—Plantago spp. The turf and landscape weeds known as plantain mainly consist of three species—broadleaf, buckhorn (left) and blackseed (right) plantain—of varying distribution. Together, they range over the entire United States and are common turf weeds. Low-growing perennials, they tolerate mowing well. Prostrate knotweed—Polygonum aviculareFound throughout the states, this weed germinates in early spring but thrives in summer. Its mats can grow up to several feet wide. It
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thrives on compacted sites. Many other members of this genus can become weedy, most of them upright growers going by the name of smartweed.Purslane—Portulaca oleraceaThis summer annual is a mat-forming plant with succulent,
fleshy stems and leaves. It commonly grows in ornamental
beds and open sites where it forms mats up to 1 or 2 feet across. The high water content of this plant’s tissue sometimes reduces herbicidal effectiveness.Russian thistle, tumbleweed—Salsola kaliMainly a weed of the Western United States, this plant is easily recognized when its dried up “skeletons” blow across the landscape. It is an annual that enjoys heat and thrives in open ground, presenting
a control challenge for fence rows and other non-crop areas. The leaves are thread-like and succulent on young plants but become shorter, stiff and pointed on mature plants.Annual sowthistle—Sonchus oleraceusSowthistle is a weed of open places, landscape beds and neglected
urban sites but does not succeed in mowed turf. This species
and a closely related type—spiny sowthistle—occur throughout the country. They grow as annuals that germinate in spring.Common chickweed—Stellaria mediaChickweed is a low, tufted winter annual. Unlike hairy mouseear chickweed, common chickweed leaves are hairless. It germinates in the fall but makes most of its growth during the following spring in cold regions. However,
it may grow considerably during winter in warmer regions.
Chickweed is troublesome
not only in beds but also in dormant warm-season turf.Dandelion—Taraxacum officinalisPerhaps the most notorious turf weed, dandelion is a low-growing perennial with a large taproot. It tolerates close mowing and can extensively invade turf. Seeds, its primary mode of spread, are distributed
widely through the air and germinate mainly in the spring but also in the fall. Its flowers can create a carpet of yellow in heavily infested turf.Poison ivy—Toxicodendron radicansPoison ivy is a woody vine that can appear shrubby at times. Occurring throughout the United States, it is more frequent east of the Rockies. It is more of a problem in fence rows and other less-used areas than in maintained landscapes, but it can persist even in mowed turf. Due to the painful allergic reaction most people have to this plant, you must diligently eliminate it whenever it starts to grow. It sprouts readily from seed. The leaves are trifoliate, and the stem of the center leaflet is longer than the other two.Puncturevine—Tribulus terrestrisThis mat-forming summer annual has sharp, spiny fruits. Found throughout most of the United States, it is most troublesome in the Southwest.
The fruits are sharp, so you must control this weed whenever you spot an infestation. The leaves are pinnately compound.White clover—Trifolium repensThis perennial is a major weed problem in turf. Its ability to spread and its tolerance to low mowing heights allow it to thrive in the turf environment. Several other related clover species also are turf pests, but white clover is the most widespread. All clovers have trifoliate leaves.Wild grape—Vitis spp.Wild grapes include several species that grow rampantly over fences, up trees and across the ground. Wild grapes are not turf pests, of course, but are difficult to eradicate once established. These woody vines commonly inhabit the periphery of landscape sites—fence lines and similar areas.TLD
Diseases of Ornamentals & Turf
The term “disease” refers to any malady that af-fects a living organism. Thus, many things in addition to pathogenic organisms can cause dis-ease: physical and chemical injury, physiological conditions and nutritional
disorders. In this chapter, however, we deal mainly with those disorders that typically fit most people’s idea of disease: pathogens. Plant-pathogenic organisms include fungi, bacteria, nematodes, viruses, viroids and mycoplasmas.Non-pathogenic diseases include phytotoxicity, nutritional
deficiencies, soil problems, graft incompatibilities,
various environmental stresses, lightning, physical injury from equipment and other conditions that can cause a plant to decline or die. We will discuss the symptoms of these problems enough to help distinguish
them from pathogenic diseases, but this chapter focuses on the latter.DIAGNOSISTo successfully diagnose plant diseases, you must be a detective and use deductive logic to come up with a list of potential causes and eliminate others. After you narrow down your list of possibilities, you then can perform lab analysis if the situation calls for it. Grounds managers often treat for probable causes using treatment response—or lack of response—as another diagnostic tool. This is not the most efficient approach but can be helpful in some cases. With luck, you can pinpoint the cause using plant symptoms, site history and reference material. If a problem has you stumped, consult an extension pathologist. These experts have vast experience
in diagnosis and are helpful in determining the cause of symptoms.Many hundreds of diseases occur on landscape ornamentals
and turf and identifying the exact pathogen is sometimes a baffling process. The first thing you must do is determine the general cause of the symptoms: pathogens, environmental factors, phytotoxicity, nematodes
or insect pests. If diagnostic symptoms are present,
your task is relatively easy. If the symptoms are more general—leaf drop, wilting or gradual limb dieback,
for example—you must investigate further. Information
to gather and questions to ask yourself include:
• Define precisely the symptoms causing you concern. This is simple in some cases but not as easy when the plant “just doesn’t look right.” Look closely and determine exactly what isn’t normal.• Determine the age and species of the affected plant. Host identity and age are important parts of diagnosis.• Observe the location of the plant relative to nearby features—parks, ponds, streets. Is the plant growing in a low spot or on a slope? Is traffic heavy near the plant? The surrounding landscape may provide clues to problems such as drainage,
drought or saline runoff.• Is exposure to chemicals a possibility? This can be one of the most frustrating problems to diagnose. So many everyday
substances can harm plants—cleaners, petroleum products, air pollution—it is difficult at times to determine
what the problem might be. Symptoms may be due to exposures you never knew occurred. Pesticide drift from careless applicators on adjacent property (or your own) is a common occurrence. Workers improperly
draining tanks of cleaning fluid or other chemicals happens as well. Keep an open mind as to what may have happened. Common phytotoxicity problems include
cupping, curling or other distortions of leaves and young shoots, burning or scorch, yellowing (especially
interveinal chlorosis) and, in severe cases, branch dieback or death.• Under what weather conditions did the symptoms first appear? What about during the past winter? Was it exceptionally cold? Did temperatures fluctuate widely? Consider conditions (rain, heat or humidity) that favor pathogens, weather that stressed the plant (making it vulnerable) or simply conditions that caused the symptoms to become visible. For example, diseases that affect vascular systems often do not become apparent until weather turns hot. Low-temperature damage may not be apparent until spring
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growth starts, when you may notice small shoots that have died. Also look for frost cracks.• Do nearby plants of the same (or different) species also show symptoms? This may provide clues about whether a pathogen
is involved.• Has construction or a change of grade occurred on the site within the last few years? If so, this may have resulted in compaction or severe root injury. This commonly results in dieback, loss of vigor, early leaf drop and eventual death of the plant.• How much growth has the plant produced over the last few years? This tells you whether the decline was gradual or sudden, which may help isolate the cause.• What cultural care has the plant received in the last few years? Improper
care may result in nutritional or water-management
problems. • Have you applied fertilizer recently? Careless fertilizing often causes burn. Fertilizing late in the fall can delay hardening,
resulting in winter damage.• Is the plant a recent transplant? Transplanting above or below grade, improper irrigation or inadequate planting holes can cause serious problems that tend to show up quickly.• What are the soil conditions—pH, soil texture, pan layers, compaction,
saturation—on the site? Poor soil conditions often cause visible symptoms.• Are the roots healthy? Dig up some small feeder roots and see if they are white and actively growing or brown and rotting. The latter indicates a root pathogen or soil conditions that are killing the roots.• What, if any, symptoms show on the trunk and large limbs? The presence of lesions, cracking or sloughing bark, fungal fruiting bodies or even mechanical wounds often indicate
the cause of the disease.• Slice open affected shoots with a knife and inspect wood for discoloration
or rot. Internal symptoms such as these indicate vascular disease or wood rot.• Inspect leaves closely. Foliar symptoms often are diagnostic.
Gathering this type of information may lead you to the direct cause or at least help you narrow it down to some type of pathogen, if not the exact one. A final point to remember is that pathogens that are present may be secondary diseases. That is, they may have moved into the weakened or wounded plant after an initial infection or other malady. For example, saturated soil often kills roots. The dying tissue serves as an entry site for soil fungi that normally would not affect healthy roots. In this case, improving drainage would be the best treatment. Plants weakened from any cause are more susceptible to infection, so you must always ensure good plant vigor.IDENTIFYING THE PATHOGENThe following are the major groups of plant pathogens and some of the common symptoms they produce.# Fungi. Fungi are the most common plant pathogens. Fortunately, many are relatively easy to treat as well. Fungi are single- or multi-celled organisms that feed on a variety of materials. In fact, most fungi are harmless—
feeding on dead and decaying organic matter—and many are beneficial, forming symbiotic relationships
with plant roots that increase plant growth and vigor. A minority of fungi cause diseases.It is difficult to generalize about fungal symptoms, which take many forms. However, when a plant has a fungal infection, you can learn a great deal about its identity by observing where and what type of symptoms the plant exhibits.• Leaves and young shoots may show lesions, scorching or discoloration on the surface and these often are diagnostic.
• Branches and trunks may display fungal fruiting bodies
or cankers. Soil and roots at the base of the trunk also may display fruiting bodies, such as mushrooms.• Roots may be dying back. Internally, some fungal infections discolor conducting
tissue (wood or phloem). Mycelium—the fungal “body” typically composed of white tissue in the form of sheet, strands or a cottony mass—may be visible under bark or on roots.# Viruses. In established landscapes, viruses most often spread as a result of two things: Either they were vectored
by an insect host that fed on the plant or they spread by contaminated pruning tools. Occasionally, however, plant material brought in from nurseries may already be contaminated. Unfortunately, it does not matter how a virus was spread—no cure exists. Occasionally
you successfully can prune out affected
112 TURF & LANDSCAPE DIGEST # 2004 chapter 14branches and eliminate the virus completely, but typically
you must remove and destroy the entire plant.Viruses cause peculiar discolorations and patterning—
mosaics, mottling or yellow rings—in many plants. Odd distortions of newer growth, generalized yellowing and stunting also occur frequently.# Mycoplasmas and viroids. These have recently come to light as plant pathogens, though it is unclear how significant they are as such. Mycoplasmas are intermediate in size between bacteria and viruses and may be the cause of diseases such as aster yellows and some witch’s broom diseases, formerly thought to be viral.Viroids are smaller than viruses, and it probably is a stretch to call them living organisms. As with mycoplasmas,
it is unclear how significant viroids are as plant pathogens. However, they are infectious and apparently cause some plant disorders that scientists previously attributed to viruses.# Bacteria. These are single-celled organisms. Some of them are significant pathogens and most are difficult to treat. Bacteria must have some means of entry into the plant—they cannot enter through an unbroken cuticle. Therefore, wounds from pruning or mechanical
injury are a frequent means of infection. Flowers are another common infection site and stomata or other openings also apparently are routes to bacterial invasion.Bacterial infections cause three general types of symptoms:• Bacterial wilt diseases result from infection of the plant’s water-conducting tissue.• Necrotic blights, rots and spots result from death of parenchyma
tissue. Fireblight is a notable example of this, as are some rots of tubers and rhizomes.• Abnormal growths, such as crown gall, are a third type.# Nematodes. These organisms are small—usually microscopic—worms that feed on plant roots. Not all nematodes are parasitic, but those that are can cause serious problems for ornamentals. Above-ground symptoms
are usually subtle, such as lack of vigor. Root symptoms are more diagnostic and include knots or other swellings of root tissue.PREVENTION AND TREATMENTPlant pathologists teach that three conditions must exist for disease to occur: The pathogen must be present,
the host must be present and conditions must be appropriate for the pathogen to infect and develop. This is the so-called disease triangle (see figure, page 113). Thinking of disease in these terms is helpful in several ways. Of course, if disease has already arisen, it’s a given that those three conditions existed. However, identifying the conditions that contributed to the disease
illustrates changes you can make to prevent future outbreaks or even cure an existing one. For example, realizing that a proper host is necessary forces you to think of alternate plant choices that may not be susceptible
to prevalent diseases. Another example: An outbreak of a pathogen that thrives in saturated soil should prompt you to improve drainage.# Preventive measures vary according to the pathogen. However, all plants are less susceptible to diseases when they are healthy and vigorous. Thus, proper cultural practices are the No. 1 preventive measure. Ensure that plants are sited properly, correct any soil and drainage problems and pay attention to ongoing irrigation and fertility management.Air circulation and light penetration are important for reducing diseases that spread via wet plant surfaces, so avoid over-planting, which reduces air circulation. Further, you may need to alter your irrigation scheduling
or change from overhead to ground-level irrigation to eliminate wetted foliage.An important practice is sanitation. Pruning crews commonly move from plant to plant with little regard for the cleanliness of their tools. Thus, many pathogens spread in this manner. If you are pruning plants that have had any history of disease, disinfect your tools with a chlorine solution (see “Sterilizing tools,” page 114) between cuts and before moving to another plant. Another aspect of sanitation involves removing dead or infected plant material from the landscape. Dead plant material, especially that which was infected while alive, may harbor pathogens that can then spread back to living plants. Thus, you should remove such material
from the site entirely or burn it. Even leaves that drop from infected trees in the fall can be a problem. Site sanitation can be as important as tool sanitation. Nursery stock occasionally is infected with pathogens—
it pays to thoroughly inspect plants before you buy them. This not only ensures a healthy transplant, but safeguards existing ornamentals to which pathogens could spread.Insects commonly vector pathogens from plant to plant while feeding. In theory, controlling these insects also should control spread of the pathogen. In practice, this often is impossible, and you should avoid indiscriminately
spraying the entire landscape with insec2004
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ticides to prevent diseases unless you are following accepted recommendations for a specific disease. Bulbs or other perennial plant parts you store for later planting are subject to certain rots. You can prevent these with good air circulation during storage. Fungicide
dusts are useful as well.# Treatment of disease is practical in many cases. However, you should accompany any treatment with a change in environmental or cultural factors that may have contributed to the disease in the first place.Fungicides are available in several formulations, and you apply them according to the type of disease you’re treating. Treat leaf diseases with a foliar spray. Vascular diseases are more difficult to treat, but trunk-injection fungicides are available for some pathogens. Root and soil-borne diseases also are difficult to treat, but you can apply certain fungicides as a soil-drench treatment.
Modern, synthetic fungicidal compounds are widely used. However, a few old remedies remain effective for treating fungi. Products containing lime, copper or sulfur are effective in preventing many types of fungal (and bacterial) infection. They do not have significant curative properties, however.Fumigation kills all living organisms in the treated soil and is an option when the site has a history of soil-borne fungi or nematodes and you want to protect new transplants.Bacterial infections are not easy to eliminate. You can prune out infected branches, which may help, and antibiotics are available in injectable or sprayable formulations.
Viruses require you to remove and destroy affected plants unless you can successfully prune out infected limbs. More often, however, you can count on losing the plant.Your treatment options for nematodes include just a few products. However, plants can tolerate moderate levels if they are vigorous. Fumigation before planting is wise on heavily infested sites.COMMON DISEASES OF ORNAMENTALSThis section lists some common fungal, viral and bacterial diseases of ornamentals, grouped by the part of the plant most affected. Many other plant diseases occur, and a good reference is helpful both for diagnosis and treatment recommendations. Again, use the services of a diagnostic lab or an extension specialist if you need help with diagnosis. Suppliers can help you select products
that are registered to control specific diseases. For a discussion of disease management in bedding plants, see Chapter 6.ROOT ROTSRoot rots are common fungal diseases of woody plants. It can be difficult to diagnose the exact pathogen because the initial symptom—decline in vigor—is common to several pathogens and can result from numerous
other factors as well. The decline can last for several years and affected plants are difficult to save. Improving drainage and maximizing plant vigor are the best ways to prevent infection. Avoid damaging root and trunks.When you remove a plant that died from root rot, eliminate as much of the old root system as possible. Then, fumigate or use a soil-drench fungicide at the site before replanting.# Armillaria—shoestring root rot. This fungus is one of the most common and widespread causes of root rot in ornamentals. Oaks, maples, firs, pines, rhododendrons
and dogwoods are common hosts. After infection, parts or all of the affected plant decline in vigor. Leaves may be dwarfed, pale and may drop prematurely. The best way to distinguish this pathogen is by the thin sheets of white mycelium growing under the bark or on the main roots. Speckled brown mushrooms often grow from the soil around the base of infected trees. The disease triangle illustrates the three conditions necessary for disease to occur. The pathogen must be present, the host must be present, and conditions must be appropriate for infection. If any of these three conditions are not met, disease will not occur. Disease-prevention strategies can address any of the three aspects: by changing conditions so that they do not favor infections (for example, providing better soil drainage), by eliminating the host (that is, planting resistant varieties) or by eliminating the pathogen (landscape sanitation and using disease-free plant material). The strategy you should use depends on the specific disease.PathogenHostFavorable conditionsDisease
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After a tree dies, dark-colored rhizomorphs—the root-like “shoestrings”—develop under the bark, over infected
roots and outward from the tree. A distinct mushroom odor normally is present. Affected plants usually die, but healthy plants can be fairly resistant. Therefore, good cultural practices are the best way to prevent Armillaria. Pull mulch and other material away from the base of the trunk to keep bark dry. Mushroom root rot, Clitocybe, is a related disease prevalent in the far South and in tropical climates. It affects plants similarly but does not develop rhizomorphs.
# Phytophthora root rot. Phytophthora is prevalent in poorly drained, infertile soils and affects many ornamentals
including both broadleaf and conifer trees and shrubs. Symptoms start with declining vigor and growth. Later, branches die back and sprouts may arise from the base of the trunk. Leaves tend to be small and drop prematurely, often curling and appearing scorched in hot weather. Affected plants eventually die.The best way to discourage this soil-borne fungus is to improve drainage. Saturated soil kills roots, which provides the fungus with entry sites. Soil-drench fungicide
applications are helpful before planting in infested
soil.# Ganoderma root rot. This is another soil pathogen that can affect numerous ornamental species and also produces
symptoms similar to other root rots. Reddish-brown conks—shelf-like fruiting bodies—appear near the base of the trunk in the first few years of infection.
Prevention is the most important aspect of managing this disease as no practical cure exists. Practices discussed
under previous root-rot diseases apply to Ganoderma.
Occasionally, you can cut out diseased roots before the pathogen spreads. STEM DISEASES# Wilts. Several fungal pathogens cause wilt in many woody ornamentals. Verticillium, oak wilt (Ceratocystis), Dutch elm (also Ceratocystis), mimosa wilt (Fusarium) and persimmon wilt (Cephalosporium) are the most serious and widespread. Most trees affected by wilt do not survive. Their leaves turn yellow or brown, wilt and then drop prematurely. This can continue for several years, or trees may die suddenly.The infamous Dutch elm disease is one wilt for which treatment is sometimes successful, if expensive. Prevention
involves severing root grafts between adjacent trees, eliminating breeding sites of the elm bark beetles that vector the fungus and pruning out affected limbs before symptoms spread. Trunk-injected fungicides are available for Dutch elm and some other wilt diseases. The best strategy is to use wilt-resistant species recommended
for your area. Fortunately, breeders have developed wilt-resistant varieties of American elm, and you should use only these for new plantings.# Pine wilt. Nematodes that colonize in conducting tissue in pines cause this disease. Some pine species are more resistant (notably white pine) than others, but none are immune. The nematode is spread by wood-boring beetles. Needles fade from their normal color and ultimately turn reddish brown upon death, which may take a few weeks to several months. Laboratory diagnosis is necessary to confirm pine wilt, but you should act promptly anytime you suspect this infection. Do not keep the wood of infected trees you’ve removed for firewood, as this may harbor borers that can then spread the disease to other pines.# Wood rots. Decay of the inner wood occurs in most trees sooner or later. This does not necessarily portend an early death, however. Affected trees can live many more years, though some may slowly lose vigor and decline. Decay fungi may produce fruiting bodies visible on the surface of the trunk. Keep trees as healthy as possible and avoid unnecessary wounding. If practical, control borers, which open entry sites for decay fungi.
# Phloem necrosis of elm. Often mistaken for Dutch elm, a mycoplasma causes this disease, which spreads by root grafting or insect vectors. Leaves of affected trees curl upward, turn yellow and then wither and drop. After the onset of symptoms, trees may die in just a month or two. There is no practical cure, and you should promptly remove diseased specimens from the WSTERILIZING TOOLSWhen you prune plants that you suspect harbor pathogens, always disinfect your pruning tools after each cut. Dip them in a 1:5 water:household-bleach solution for 30 seconds and then in 75 to 95 percent grain or rubbing alcohol for the same amount of time. This sterilizes your tools and prevents the pathogen from spreading to healthy tissue while you prune.
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landscape. To distinguish this disease from Dutch elm and other similar maladies, look at the inner bark near the trunk base—it will be yellow or butterscotch colored
and may contain dark flecks.# Cankers. Cankers are lesions (dead spots) that develop
in the bark of twigs and branches. Cankers often develop in open wounds and can enlarge until they girdle entire limbs. Fungi cause nearly all cankers, although
a few bacterial cankers occur as well. With few exceptions, chemical treatments are ineffective. Cankers can girdle entire branches and ultimately will kill the host.If you spot cankers on smaller branches, prune these limbs out, making the cuts at least 6 inches below any sign of the canker. On large branches or trunks, it is sometimes possible to eliminate cankers with surgical removal. Use a sharp knife to cut away the cankerous tissue, making the cuts within healthy tissue just outside
the infected area. Disinfect the tool between cuts and immediately cover the wound with shellac. Although
cankers usually infect tissue just inside the bark, the fungi sometimes penetrate into the underlying
wood. In this case, remove the discolored wood as well.Severely affected plants are probably lost causes, so cut them out and remove their debris from the landscape entirely. # Wetwood. The primary symptom of wetwood is oozing of slime flux—slimy, dark, often smelly sap that drains from trunk wounds and wets the bark below. This chronic condition can result in a slow decline of the tree. Elms and poplars are the most commonly affected
trees, though numerous other hardwoods are susceptible.Wetwood results from bacterial infection of spring-wood parenchyma cells. No practical treatment exists, but fertilizing with nitrogen may help trees overcome the effects of wetwood.# Witches’ brooms. These peculiar growths are the plant’s physiological reaction to a fungus, virus, bacterium,
insect or even mistletoe. Witches’ brooms are dense masses of dwarfed shoots that are especially conspicuous in dormant deciduous trees. To control them, simply prune them out.# Galls. These growths often are the plant’s reaction to attack by insects but also result from many other pathogens. No treatment exists for galls, and controlling the agents that promote them is a strategy that is not often effective. Fortunately, galls seldom cause life-threatening injury to ornamentals and the best approach is tolerance. Though not attractive, they are not typically
lethal, and you can do little about them anyway, except to prune out those that are particularly unattractive.
# Crown gall. This gall—whitish at first, then turning dark—is somewhat different than most galls that affect leaves and young shoots. Crown gall causes large tumor-like growths on stems, trunks and even roots of many species of plants. The causal bacterium is Agrobacterium tumefaciens and persists in soil for several years. Therefore, do not replant susceptible species in the same spot where an infected plant grew previously. If possible, prune out branches that display galls, sterilizing tools between cuts.LEAF DISEASESLeaf diseases generally do not pose a serious risk to trees and shrubs. They may cause early leaf drop, and several successive years of this can deplete food reserves to some extent. However, this usually is the most serious
consequence, and trees generally tolerate it. Infection
ends as soon as leaf fall occurs in late summer or fall. Evergreens are more vulnerable, because leaf drop may remove several years of leaf growth. Therefore,
you should give evergreens higher treatment priority than deciduous plants, with which landscape managers usually tolerate foliar diseases.# Powdery mildew. This disease is common to a great many ornamentals, though it rarely is a serious threat to plants. It is, however, unattractive—its superficial white, powdery growth on leaves is easy to spot. Powdery
mildew is most frequent in shaded or crowded plantings with poor air circulation. Improving this factor
alone often alleviates mildew problems. Otherwise, several products easily control powdery mildew. Anti-transpirants apparently can reduce outbreaks of this disease.# Fireblight. The bacterium Erwinia causes this disease, and it is a serious problem for plants of the rose family. Affected leaves, flowers, shoots and fruits suddenly turn brown or black and look as if they’ve been scorched by fire. Cankers also may appear on twigs and branches. The pathogen spreads by splashing water, wind or contaminated
pruning tools.Prune out affected shoots 6 to 12 inches below any sign of infection, disinfecting tools between cuts. Streptomycin
is an effective bactericide for use against fireblight.
Also, plants vary widely in their susceptibility, so use resistant varieties.
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# Anthracnose, leaf blight, leaf blotch, leaf spots, shot hole and scab. These diseases, caused by a variety of fungi (a few bacterial leaf spots also occur), can affect nearly every woody ornamental and are quite common. No fundamental distinction exists between most of them; they all cause necrotic areas of various sizes and shapes. These affect leaves and, often, entire young shoots. This is not to say that symptoms are not distinct enough to be diagnostic—many are. Symptoms of scab, leaf spot and shot hole include round, oval or angular spots with raised or sunken centers which may fall out, creating “shot holes.”Anthracnose, leaf blight and leaf blotch produce larger, more irregular dead areas that m ay extend to give entire shoots a scorched appearance. Little basis exists for differentiating between the three, and the terms often are used interchangeably.Though unattractive, most of these diseases are not particularly injurious to trees and shrubs. Therefore, it is difficult to justify control measures except for valuable specimens. Sanitation, such as removing fallen leaves in the fall, may reduce the incidence of these diseases.Anthracnose is practically an annual occurrence in many areas. It causes much fretting by grounds managers
concerned about the defoliation that this disease causes, sometimes two or even three times in a single season. While this can weaken trees, fungicidal treatments
are expensive and not financially justified in most cases because trees generally recover adequately once weather becomes warm and drier. However, particularly valuable trees or shrubs may warrant treatment,
for which several effective products are available. Consult with local extension pathologists for recommendations.
# Needle blight, spot or cast. These consist of spots or lesions on the needles. Needle cast is the term that describes the advanced stages when needles actually drop. Not fundamentally different from leaf spot on broad-leaved plants, these diseases (many pathogens cause them) are not usually serious unless they advance to the point that needles begin to drop in large numbers.
In this case, treatment may be necessary to prevent defoliation which, as stated previously, can be more serious for evergreens than deciduous plants.# Rust. This is a peculiar group of fungi, some of which require two different hosts to complete their life cycle. Yellow, orange, red, brown or even black pustules develop on the undersides of affected leaves, which may drop early. The spores are wind-borne, and the disease—though it is not typically serious—can stunt or even kill a plant outright in severe cases.In cases where the fungus requires an alternate host, destroying the alternate host plants growing in the general area often suffices for control. The classic example of this type of situation is cedar-apple rust. A common disease of apple and crabapple trees, this rust also requires Juniperus spp. to complete its life cycle. Thus, if you can eliminate all nearby juniper hosts—such as the weedy eastern red cedar—within several hundred yards of the trees, the disease should be much less severe. Unfortunately, this measure often is impractical. Fungicidal treatments work well but may require 4 or 5 applications. Therefore, many landscape managers simply tolerate the disease.# Sooty mold. This “disease” results from mold that grows on honeydew secretions of insects such as aphids or whiteflies. This creates black or gray patches on the leaf surfaces. The fungus is not parasitic to the plant, merely unsightly. If, for some reason, you must eliminate
sooty mold, the best strategy is to treat for the insects themselves.# Leaf blister or curl. Blister diseases are similar to leaf spots and anthracnose in the sense that they affect many plants but rarely in a serious way. Symptoms include wrinkled, curled or puffy “blisters” of various colors on leaf surfaces. Affected leaves usually drop early. Again, treatment is possible but not usually warranted.
# Mosaic and ringspot. The symptoms of mosaic and ringspot—mottling and circular lines or other odd markings—result primarily from viral infection. The foliar symptoms of these two diseases can be quite distinctive. A general decline in vigor and stunting often occur in conjunction with foliar symptoms or alone. No practical treatment exists, though some grounds managers attempt to prune out infected shoots before the virus spreads, with occasional success. The usual action is to remove severely infected plants. Virtually all plants can develop some type of viral infection, but viruses are not one of the major plant-disease problems most landscape professionals face.# Lethal yellowing. This disease has killed large numbers of palm trees in Florida since its introduction in the 1970s. It is caused by a mycoplasma-like organism
that infects conducting tissue. Initial symptoms include fruit drop and necrotic flower parts. Foliar symptoms follow and may include the appearance of bright-yellow leaves in the middle of the crown or, in some species, leaflet browning or general leaf discol2004
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SYMPTOMATIC KEY TO DISEASES OF KENTUCKY BLUEGRASS, PERENNIAL RYEGRASS AND FINE-LEAF FESCUE TURF.DiseaseSeasonPrincipal hosts/CommentsLeaf spots on leaves or sheathsLeaf spots brown or purple-brown, oval-shaped or elongated. The centers of spots nay develop a tan color. Turf may be thinning out in irregular patterns.Helminthosporium leaf spotSpring, Summer, FallAll turfgrasses, especially common-
type cultivarsLeaf spots are hour-glass-shaped, bleached tan or straw-brown in color and extended across the entire width of the blade. Leaf spots are normally bordered by brown, purple or black bands. Affected patches are circular and 2 to 6 inches in diameter.Dollar spotSpring, summer, fallAll turfgrasses, especially poorly nourished sites.Affected areas dead or thinning in circular patches, spots or ringsCircular patched of matter on leaves appearing late fall, winter or early spring. Generally appearing at snow melt or in the presence of plenty of surface moisture during cool/cold overcast periods. Patches 1 inch to 2 feet in diameter, matted leaves have a pinkish or red-brown color, Center of patches may be leached white in color. Patches 6 inches to 3 feet in diameter; matted leaves have a grayish color. Scierotia may be present.*
Pink snow mold Gray snow moldLate fall, winter or early spring Late fall, winter or early springAll turfgrasses, especially annual bluegrass and perennial ryegrass All turfgrasses, especially Kentucky
and annual bluegrassCircular, straw-brown spots 2 to 6 inches in diameter; straw-brown, hour-glass-shaped lesions on leaves.Dollar spotSpring, summer or fallAll turfgrasses, especially poorly nourished turfCircular or irregular patches 3 to 12 inches in diameter. Leaves water-soaked and covered with a pink gelatinous
fungal growth. Dead leaves in center of affected areas are straw brown, tan or slightly pinkish in color. Red, brittle, threadlike strands extend from tips of dried grass blades.Red threadSpring and fall, and prolonged rainy periods in summerAll turfgrasses, especially perennial
ryegrass and fine-leaf fescueCircular patches 6 inches to 2 feet in diameter. Affected areas are brown; outer margin of diseased patches may have a grayish "smoke ring." Leaves blighted, and chocolate-brown lesions present.Rhizoctonia brown patchJune-Sept., night temps above 68°F, high day temps, high relative humidityAll turfgrasses, especially perennial
ryegrass and tallfescueCircular or irregular patches and rings with living grass in the center (Frog eyes). Patches initially 1 to 2 inches, increasing to 6 inches to 2 feet in diameter. Patches may be sunken, and leaves at the periphery may have a bronzed appearance. Tip dieback of leaves give turf a straw-brown color.Summerpatch/Fusarium blightJuly to early September
Primarily Kentucky bluegrass and fine-leaf fescue turf older than two years of age.Circular spots 1 to 3 inches in diameter, leaves are grayish
or water-soaked, and mycelium is normally present on leaves during early morning hours, Leaves are rapidly blighted, and entire plants die in 24 hours. Lead plants are brown or red-brown in color.Pythium blightJuly to early September
Primarily perennial ryegrass, especially during hot and humid periods and in poorly drained sites; seedlings of all species planted during warm and humid periods are susceptibleRings or arcs of dead grass bordered by inner and outer zones of dark green grass or rings of luxuriant grass without a dead zone. Rings 1 to 4 feet in diameter or larger. Mushrooms may grow in ring.Fairy ringsAll yearAll turfgrass, especially droughty sites and poorly nourished turf*Sclerotia are compact masses of fungal mycelium covered with a protective rind. Gray snow mold sclerotia are chestnut brown or black in color, 0.125 to 0.375 inches in diameter and are usually found embedded in sheaths or on leaves of diseased turf during spring following snow melt.TABLE CONTINUED
118 TURF & LANDSCAPE DIGEST # 2004 chapter 14
SYMPTOMATIC KEY TO DISEASES OF KENTUCKY BLUEGRASS, PERENNIAL RYEGRASS AND FINE-LEAF FESCUE TURF.DiseaseSeasonPrincipal hosts/CommentsAffected areas dead or thinning out in an irregular patternTurf thinning out and brown or red-brown in appearance from a distance. Brown or purple-brown, oval-shaped leaf spot lesions on leaves and sheathes.Helminthosporium melting outPrimarily during wet, overcast periods
in spring/fallAll turfgrasses, especially poorly nourished or excessively fertilized common typesLeaves bearing parallel black or silvery-gray stripes that extend the length of leaves. Leaves eventually shred and curl along lines releasing black, powdery spore masses. Leaves may be yellow.Stripe or flag smutSymptoms noted in spring and fall, but may succumb during
hot, dry periods in summerPrimarily Kentucky bluegrass older than 3 years of ageLeaves bearing red, orange, yellow or black pustules. Turf has a yellow or reddish appearance from a distance.RustPrimary late summer
and fallAll turfgrasses, especially perennial
ryegrass, Kentucky bluegrass and zoysiagrassMold or other residues on leavesGray or black, cigarette-ash-like residue on leaves. Crusty material (fruiting structures) is easily rubbing off and appears after a prolonged rainy period. Moldy residue may form on plants in rings or arc patterns.Slime moldSpring, summer and fall, especially after prolonged rainsAll turfgrassesLeaves with black or silvery-gray stripes that rupture, causing leaves to shred and curl, releasing black, powdery
spore masses.Stripe or flag smutPrimary spring and fallPrimarily Kentucky bluegrass older than 3 years of ageLeaves bearing red, orange, yellow or black pustules. Turf yellow or reddish in appearance from a distance.RustPrimarily late summer
and fallPrimarily perennial ryegrass, Kentucky
bluegrass and zoysiagrassLeaves bearing a whitish or gray moldy growth. Leaves eventually turn yellow.Powdery mildewPrimarily late summer
and fallAll turfgrasses, especially Merion Kentucky bluegrass; normally occurring
on turf in shaded areasTechnical credit: Peter H. Dernoeden, University of Maryland, Agronomy Mimeo 84, Department of Agronomy, 1987.SYMPTOMATIC KEY TO DISEASES OF TALL FESCUE TURFTall fescue is widely used as a turfgrass. Its strengths include good drought tolerance, moderate fertility needs and good disease resistance.
Tall fescue is susceptible to Helminthosporium net blotch, crown rust, pink and gray snow mold, red thread and brown patch. Of these diseases, only Helminthosporium net blotch and brown patch are considered common diseases of tall fescue turf.Helminthosporium net blotchSeasonInitially, symptoms appear as minute brown or purple-brown specks on leaves. As the disease advances to dark brown, net-like patterns of transverse
and parallel lines of necrotic lesions develop on leaves providing a net-blotch appearance. These net blotches may coalesce, and leaves turn brown or yellow and die-back from the tip. Under ideal conditions, stand density deteriorates.Cool, moist periods of spring and fallRhizoctonia brown patchSeasonLeaves severely blighted, bearing elongated, tan lesions with chocolate-brown margins. Disease is more severe under high mowing heights and may reduce stand density.Cool, moist periods of spring and fallTechnical credit: Peter H. Dernoeden, University of Maryland, Agronomy Mimeo 84, Department of Agronomy, 1987.
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orations that range from gray to brownish red. You can extend the life span of—but you cannot cure—infected palm trees with oxytetracycline injections.
However, it may be better to remove infected trees so the disease does not spread to other palms. Some landscape managers use oxytetracycline as a preventive measure for valuable palms growing in infested areas. The best strategy, however, is to use palm species and cultivars resistant to lethal yellowing.
TURF DISEASESMost turfgrass diseases are caused by pathogenic fungi that invade the leaves, stems and roots of plants, thereby causing various symptoms such as leaf spots, root rots or death of entire plants. Sometimes these fungi produce visible structures such as mushrooms, white powdery mildew or a fluffy, moldy growth. These fungi are normally present in most lawns, but disease only occurs when environmental factors favor growth of the pathogen and increase the susceptibility of the grass host. This relationship between the environment,
host and pathogen are the key factors in disease causation and control. Turfgrass management practices alter the environment and therefore have a major impact on disease development. These management
practices include mowing, irrigation, fertilization,
thatch control, traffic and soil pH.Mowing favors infection and disease by creating wounds through which a pathogen may enter the plant easily. Mowing also spreads fungal spores and mycelium. Height of cut is a major factor in disease susceptibility. Close mowing predisposes turf to Helminthosporium diseases, rust, powdery mildew, brown patch and dollar spot disease. The continuous removal of the youngest, most photosynthetically productive tissues when mowing below recommended
heights causes depletion of food reserves in the grass plant. These reserves are needed for active disease-resistance processes in plants, and plants also use them to recover from injury.Irrigation provides moisture critical to spore germination
and fungal growth. The timing, duration and frequency or irrigation may greatly affect disease intensity. Light, frequent irrigation discourages root development and predisposes turf to injury when extended periods of drought occur. Subjecting turf to drought stress appears to favor Helminthosporium diseases, stripe smut, powdery mildew, summer patch, dollar spot and fairy rings. Excessive irrigation also restricts root development and encourages disease.
Turfgrasses grown under wet conditions develop succulent tissues and thinner cell walls that pathogens
presumably more easily penetrate. Algae and mosses thrive in waterlogged soils, particularly where turf density is poor. Morning or afternoon irrigation is often recommended during summer to ensure that plant tissues are dry by nightfall. This practice helps minimize the intensity of Pythium blight and brown-patch disease.Use of proper soil-fertility programs improves the vigor of plants and their ability to resist disease. Excessive
use of nitrogen promotes tissue succulence and thinner cell walls, which as previously mentioned,
pathogens more easily penetrate. Conversely, turfgrasses growing in nutrient-poor soils are prone to invasion by dollar spot, red thread and rust diseases.
Application of nitrogen to diseased turf under low-fertility conditions stimulates growth at a rate that exceeds the capacity of the fungus to colonize new tissues, thus reducing the level of disease injury.
Many turfgrass pathogens survive as resting structures
or as saprophytes (organisms living on dead organic matter) in thatch. Thatch also provides fungi with moisture. Fungal pathogens such as Helminthosporium
spp. produce enormous populations of spores in thatch, particularly when the thatch is subject to frequent wetting and drying. Stripe smut, Helminthosporium and summer patch are diseases that appear to be favored by excessive thatch accumulation.
Traffic, like mowing, produces wounds that some fungal pathogens easily invade. Compaction caused by heavy traffic impedes air and moisture movement into soil and eventually restricts root function, causing
a decline in plant vigor and disease resistance. Soil pH also may affect disease development in turfgrasses.
For example, extremes in soil pH result in reduced plant vigor and, therefore, a reduction in plants’ ability to resist disease.As with ornamental plants, you diagnose turf plant diseases using signs and symptoms. Signs represent the visible parts of the pathogen—for example mycelium,
fruiting bodies, resting bodies and spores. Symptoms are the outward expression of a plant that is suffering from a disease. Symptoms include, for example, leaf spots, tissue blighting, rots, yellowing, wilting and stunting. Symptoms of most turf diseases take the form of leaf-spot lesions, blighting of leaves, water-soaking of leaves, and crown and root rots. A symptomatic key to common lawn diseases is provided here. Control of diseases by the use of fungicides may become necessary in some situations.
Managing Insects & Related Pests
Insect species number in the millions worldwide. Although
they make their livings in a variety of ways, a great many do so by consuming vegetation. It is not surprising, therefore, that insects constitute one of the major pest groups of turf and ornamentals. Mites, another
group of serious plant pests, are related to insects but more closely to spiders. However, it is convenient to include them with insects when discussing control measures.
Other plant pests—such as snails, slugs, millipedes and centipedes—fall into other groups. The one thing these groups have in common is that they are all invertebrates.
We’ll deal with several kinds of invertebrate pests in this chapter. However, in practice, the vast majority
of invertebrates with which you must deal in landscapes will be insects and mites.Recognizing damage is an important step to managing insects and mites, because you usually see these signs before you actually spot the pest itself. When you do see the signs of infestation, they often tell you the general type of pest present, if not the exact one. Then you’ll know where to look further, if necessary.Insects generally feed by either chewing plant tissue or piercing the plant tissue and sucking out plant fluids. An insect’s mouth parts and its method of feeding determines
the type of injury it causes. For example, an insect with biting/chewing mouth parts damages plants by physical removal of plant tissue, such as pruning roots, notching out leaves or hollowing out crowns and stems. Insects with piercing-sucking mouth parts, on the other hand, damage plants more subtly by leaving the plant intact and removing fluids. This is an important distinction
because of the implications it has for control measures
as well as diagnosing damage to determine which pest is responsible.The keys to controlling insect pests are:# Identify the pest.# Understand its life cycle.# Select and apply an appropriate control method.The following sections describe important landscape pests. Because insect pests, insect damage symptoms, microenvironments and control strategies differ among turf and ornamentals, we will discuss turf insect pests and ornamental insect pests in separate sections.TURF INSECTSTurf insects can be broadly divided into three separate EuropeanchaferMay or June beetle*Japanese beetleOrientalbeetle* The genus Phyllophaga includes more than 100 North American species, which are usually referred to generically as May or June beetles. Fewer than 10 of these species account for most of the damage caused by May or June beetles, and their rasters all resemble the generalized pattern shown here. Asiatic garden beetleHeadBlack turfgrass ataeniusGreen June beetleNorthern or Southern
masked chaferAphodius spp.RasterThe raster is located on the ventral side of the last segment of the grub.
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groups depending on the environment in which they are found: soil, thatch, or leaves and stems. Those in soil generally feed on turfgrass roots. Thatch-inhabiting insects
live in thatch and feed on turfgrass leaves and stems. Leaf-/stem-inhabiting insects are found almost solely on leaves and stems.SOIL-INHABITING INSECTS# White grubs. White grubs, the larvae of several closely related species of scarab beetles, are perhaps the most common and troublesome soil-turf pests on a national basis. The species involved vary from one region to another,
but several characteristics remain constant. The grub typically is cream-colored with a brown head capsule,
has three pairs of legs and often curls into a “C” shape. It ranges from 0.125 inch long when young to 0.5 to 1 inch long when fully grown, depending on the species.
• Life cycles. Most white-grub life cycles fall into one of two patterns. The most common is the 1-year cycle. The insect spends the winter just below the frost line as a full-grown grub. In the spring, as soil temperatures begin to warm, the grub migrates upward, back to the root zone, where it feeds on roots for 6 to 8 weeks (April to June). In late spring, the grub pupates and emerges as an adult about 1 to 3 weeks later.The adults of the various species differ in appearance and habits. Some, like the Japanese beetle, are active during
the day and feed on the foliage of ornamental plants. Others, like the European chafer, are active at night. Adults mate and females begin to lay eggs in the soil (June to August). These eggs hatch into tiny grubs that immediately
begin to feed on grass roots. The grubs molt twice as they feed and grow. They reach the third (largest)
stage by September and feed into October or November
before migrating downward in the soil for the winter. Some species have a 2- or 3-year cycle, particularly in the cooler regions. In these cases, the insect spends an extra year or two in the grub stage, feeding throughout the growing season and moving deeper into the soil each winter.• Symptoms. Damage typically is most obvious in September
and October and again in April and May, when the grubs are largest and hungriest. Grub damage is more obvious when turf is under stress.Turf first appears wilted even under irrigation. Upon closer examination you’ll find that the turf can be pulled up like a carpet due to the grubs’ root feeding. Skunks, birds, moles and even armadillos often feed on grubs and tear up turf in the process.• How to identify white grubs. The best characteristic to use for grub identification is the rastral pattern—the arrangement of the small hairs and spines on the raster, the ventral side of the grub’s posterior end (see illustration
page 120). This patterning is characteristic for most species. You can view it with a 10x eyepiece, available from many suppliers and surplus outlets. Although numerous kinds of grubs exist, a relatively small number are responsible for most damaging infestations.
On page 119, we show the most important species you’re likely to encounter. To find out which species is damaging your turf, match the rastral pattern you see to one of those shown on the previous page.# Mole crickets. Mole crickets (see illustration at below) are relatives of grasshoppers that are well adapted to burrowing in soil. They have an enlarged thorax (shoulder
region) that pushes soil and strong, thrusting hind legs. The front legs are enlarged and act like spades for digging and like scissors for cutting small roots. The body is light brown and usually is covered with light brown, velvety hairs. Adults are 1.0 to 1.5 inches long. Immature mole crickets resemble adults except that they are smaller
and have very small wing pads. All stages feed on grass roots and tunnel through the soil, often causing the turf to dry out. Mole cricketWirewormJapanese beetle
122 TURF & LANDSCAPE DIGEST # 2004 chapter 15Mole crickets are most common in the Southeast and can cause significant damage on a variety of warm-season turfgrasses. The Changa and Southern mole crickets are the most common and troublesome species in the Southeast.
The Northern mole cricket occurs much less frequently.
Mole crickets spend the winter months as adults. In the spring, the adults burrow several inches into the soil and lay up to 35 eggs in a cell. Eggs hatch in 2 to 3 weeks, usually in May or early June, and the nymphs (immatures)
begin feeding on the roots of various plants. Most individuals complete their development by late fall and spend the winter as new adults, deep in the soil. Mole crickets tend to be most active at night and can cause a nuisance in the spring when adults are attracted to lights during mating flights.# Wireworms. Wireworms (see illustration on page 121) are the larvae of click beetles and occasionally occur in large numbers among turfgrass roots. They are slender, shiny, relatively hard-shelled, about 0.5 to 1-inch long and usually dusty brown. Wireworms have a long life cycle. Adults often live for nearly a year and lay eggs near grass roots. Wireworm larvae hatch and spend 2 to 6 years in the soil, depending on the species. Generations often overlap, so adults and larvae are present at the same time. Adults are not particularly
mobile, so populations can build to significant levels over the years. Wireworms seldom cause serious turf damage, even when they are present in large numbers. Damaged turf has irregular dying or dead patches in which roots are partially eaten. # Billbugs. Several species of billbugs (see illustration at left) damage turfgrass throughout the United States. Some of the more common species are the hunting billbug on zoysiagrass, the Phoenix billbug on bermudagrass and the bluegrass billbug on Kentucky bluegrass.Billbug larvae are small (0.25 to 0.375 inch), legless and cream-colored with brown heads. They often have a gray or black patch in the middle of the back, and the mid-section usually is noticeably broader than the head. Billbug adults are weevils (beetles with long snouts). The body is black, appears somewhat pointed at each end and is relatively broad in the shoulder region.Most billbug species overwinter as adults in protected areas. In the spring, the adults begin to move around, and you often can find them on driveways or sidewalks adjacent to turf. Adults lay eggs in May and June. The eggs hatch in about 2 weeks, and the young larvae feed inside the grass stem for a while before moving down the stem to feed on the crown. The larvae pass through several molts, feeding as they grow, and end up feeding in the root zone.In northern regions, larvae are most abundant in July and August. They complete their development in August, pupate and emerge as adults. You may find these new adults in large numbers on driveways and sidewalks in September and October. As cooler weather approaches, the billbugs find shelter in hedgerows or other protected areas and prepare for winter.You readily can pull billbug-damaged turf out by hand because the stems break off at the crown. Often larvae feeding in the root zone leave behind a fine white material
that looks like sawdust. The sawdust-like material is a good indication of billbug activity.Usually, by the time billbug damage becomes noticeable,
it is too late to get satisfactory control with pesticides.
Successful control depends on anticipating the problem. Watch for billbug adults on nearby sidewalks in the spring. If more than five billbugs are observed during a 5-minute period, consider applying an insecGround
pearls0.25 inchBlack turfgrass AtaeniusBillbug
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ticide to the affected turf areas. Make the application on newly mowed turf (generally in June or early July) and water it in lightly to move the material into the thatch, where the young grubs are active. # Black turfgrass Ataenius. The black turfgrass Ataenius (BTA) (see illustration page 122) is a close relative of white grubs, but the life cycle is markedly different. The grub resembles the white grub (cream-colored, three pairs of legs, C-shaped), but it is much smaller—only 0.25 inch long when fully grown. BTA overwinters as adults in protected areas, such as clumps of tall fescue or ground covers, and migrates to turf areas in early spring. Adults mate, and females lay eggs in May or early June. Grubs hatch in about a week and begin feeding. They pass through two molts and reach the largest grub stage in June or July. These grubs then pupate, emerge as adults and usually lay eggs to produce a second generation of grubs. This generation feeds on turf roots in August and early September, pupates and emerges as adults in September. These adults migrate to overwintering sites later in the fall. Damage is most apparent in July, particularly if the weather is unusually warm, and again in August. Damage resembles drought stress and can cover large turfgrass areas, such as an entire fairway, if the insect population develops unchecked.The best time to control BTA is when adults are laying eggs in the spring. Timing is critical but should be correct if your applications coincide with the flowering of Vanhoutte
spiraea or black locust. Lightly water these applications
in because the adults reside in the thatch. Do not water so heavily that you wash the insecticide past the thatch and into the soil below. Another control alternative is to treat the soil to kill young larvae as they hatch. Make these applications from late May on, depending on the local weather and grub activity. Timing is not as critical, but you must water these applications into the soil thoroughly for them to be effective. In general, once damage is evident, control won’t be effective. This is because grubs have already finished feeding and will not be affected by the insecticide.
# Ground pearls. Ground pearls (see illustration on page 122) are tiny scale insects that attack the roots of many warm-season grasses, particularly bermudagrass and centipedegrass. The life cycle of ground pearls is not well understood. Apparently mature females emerge from their protective shells, move a short distance and lay eggs in the soil. Nymphs hatch and attach themselves by their mouth parts to nearby roots and remain for the duration of their development. Nymphs suck nutrients from the roots, begin to grow and produce a hard, pearl-like shell that may become as large as 0.19 inch in diameter. A typical generation (egg to adult) takes at least 1 year to complete and may take 2 or 3 years. Damage from ground-pearl activity is caused by the pruning of fibrous roots and removal of plant fluids. Turf turns yellow, resembling drought stress, and eventually brown. Damage appears in irregular patches. Insecticidal control is extremely difficult, partly because
the insect spends virtually all of its life cycle protected
by a hard, waxy shell that insecticides cannot penetrate. Furthermore, ground pearls may develop at depths up to 10 inches. The best approach to their control is to provide optimum growing conditions, particularly in terms of irrigation and fertilization, to enable the turf to tolerate ground-pearl activity. CutwormSod webwormChinch bugs
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THATCH-INHABITING INSECTS# Chinch bugs. Chinch bugs (see illustration page 123) are small, white-and-black insects about 0.20 inch long when fully grown. They suck plant juices from grass plants. Severe feeding causes yellowing of the turf in spots. These spots often turn brown and die. In many instances, damage
takes place without the chinch bugs being observed.
Several different species of chinch bugs occur in the United States, but only a few are known to cause damage to turf. One species, the southern chinch bug, infests St. Augustinegrass and other grasses. The hairy chinch bug, commonly found in the Northeast and Upper Midwest, feeds on bentgrasses, fescues and Kentucky bluegrass.Life cycles are similar between the two species. The black-and-white winged adults overwinter in taller grass and debris. The Southern chinch bug continues to be active during winter in the South, but its development is slow. In spring, adult chinch bugs move from hibernating sites to growing turfgrasses where they feed and mate. The female chinch bugs lay about 100 to 500 eggs over a 3- to 4-week period.Eggs hatch into tiny, red-and-white nymphs about half the size of a pinhead. These nymphs feed on plant juices and continue to grow. As they enlarge, they shed their skins four times before becoming a winged adult. With each shedding, the nymph increases in size, becoming black with a small white area between the wings. The wings of the adult are white.In the northern United States, two generations of chinch bugs generally hatch each year; in Florida, Louisiana
and other Southern states, the Southern chinch bug may have overlapping generations. In late summer, the population in turf can build up to 200 to 300 per square foot. Both adults and nymphs are found in sunny areas in uneven clusters or patches, not distributed uniformly over the lawn. When chinch bugs are numerous, you’ll find them on sidewalks, driveways and even on the sides of houses.To determine if chinch bugs are causing damage, it often is necessary to flood them out of their feeding sites. A simple method is to remove the bottom of a metal coffee can and drive the can into the soil at the periphery of the damaged area. Fill the can with water and check for chinch bugs floating in the can for the next 5 minutes or more.# Sod webworms. Sod webworms (see illustration on page 123) are the larvae (caterpillars) of a number of moth species. Of those species attacking turf, the vagabond webworm, silver-striped webworm, bluegrass webworm, tropical sod webworm, and the lawn or large sod webworm
are most damaging. One sign of sod webworms is the presence of small buff-colored or almost-white moths flying just above the grass in a zigzag pattern in the early evening hours. These moths collect around lights and screens after dark. When at rest, the moths are tubular in shape because of how the wings wrap around the body.Most sod webworms pass the winter as larvae, tightly coiled in a closely woven silk case covered with particles of soil. In the spring, the webworms change into pupae within cells in the soil. Adult moths soon emerge to mate and lay eggs. Eggs are laid by the female sod-webworm moths while flying low over the turf in the evening hours. Eggs hatch after about a week, and the young webworm larvae begin feeding on turfgrass leaves.Sod-webworm damage results from feeding larvae—the adult moths do not feed. Sod webworm larvae construct
silken-lined burrows or tunnels in the thatch. Their feeding consists of clipping off the grass blades just above or at ground level and eating them. Most feeding occurs Clover mite (highly magnified)Aphid or greenbugArmyworm
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at night and in the early morning. The larvae hide in their burrows during the day.In healthy turf, a considerable number of webworms are necessary to cause visible damage—in most instances, at least six webworms per square foot of turf. Usually, the first generation of sod webworms in early summer are not numerous enough to cause damage. But in each succeeding generation, 6 to 8 weeks later, the number of webworms can greatly increase. The caterpillars have bigger appetites as they grow larger, reaching a full size of 0.75 to 1 inch long. They are gray to dusky-green with a dark brown head and brown spots over the body. Most areas of the United Sates have 2 or 3 generations a year. Sod-webworm feeding first causes small, irregular areas of dead or dying turf. These small patches merge as they enlarge from continued webworm feeding. If the number of webworms in the turf is high, they can severely
damage the turf in a few days. Badly damaged turf has many ragged, uneven patches of dead grass. Pencil-sized holes are produced by birds digging webworms out of their silken burrows. Much of this bird feeding occurs in early morning. # Cutworms. Cutworms (see illustration on page 123) that damage turf include several types: black cutworm, variegated
cutworm and bronzed cutworm. Cutworms are a group of thick-bodied, dull-brown, gray or dull-black caterpillars up to 1.5 to 2 inches long. These caterpillars usually live in the soil or just under the soil surface during
the day and feed on the turfgrass at night. Some species eat only grass leaves, while others cut off plants at the soil surface. When you find cutworms resting in the soil during the day, they commonly are in a curled position—the same posture they assume when disturbed.
Adult cutworm moths are active at night and common around lights and on windshields. They are dull-black, gray or brown with a wing span of about 0.5 inch.# Armyworms. The armyworm (see illustration page 124) commonly overwinters as a larva or pupa. The worms are green with black stripes down the center of the back and along each side. They measure about 1.5 inches long when fully grown. Adult moths are bright brown with a white spot near the center of each front wing. The moths often appear in large numbers around street and building lights in summer. The eggs are greenish-white and laid in rows on the lower leaves of grasses. Three generations of armyworms commonly hatch each year. Armyworms cause damage by devouring grass, usually in circular patches. An “army” of worms hatching from egg clusters in a concentrated area can completely eat the grass from a small area before migrating to other areas in the lawn. These insects feed more commonly at night but do not hide completely during the day.LEAF-INHABITING INSECTS# Aphids. Aphids, or plant lice (see illustration on page 124), are soft-bodied, usually wingless, slow-moving insects. Certain species, such as the greenbug or the oat-bird cherry aphid, have been observed feeding on turfgrass, especially bluegrasses. Aphids form a “crowd” on turfgrass leaves and stems and suck juices from them.The damage caused by aphids is similar to that of other sucking insects such as chinch bugs. Infested areas are circular with the grass turning yellow or dying.
These patches are common in the shaded areas under trees. Close examination of the outer edge of the damaged area will reveal aphids massed on the grass leaves. Black vine weevilElm leaf beetleScales
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# Mites. Mites (see illustration on page 124), which are relatives
of insects, are small and difficult to see without a hand lens or magnifying glass. Mites are eight-legged, wingless and usually oval-bodied. They feed by sucking sap from grasses, causing mottling or blotching of the leaves. Severe feeding by high populations of mites can kill turfgrass. Several species of mites can occur in lawns anywhere in the United States. Spider mites are yellowish or greenish, often with two or more dark spots on the body. They feed on many plants including grasses. The white, worm-like bermudagrass mite feeds on bermudagrass in the Southwest.
Another important species
is the clover mite. These greenish to reddish-brown mites feed on clovers and other plants in addition to turfgrasses. They are more of a household pest, however, migrating up the exterior walls of homes. They often find their way inside homes in late fall, winter and early spring, crawling on window sills, drapes and the insides of windows.Mite control with chemicals is not often necessary. Only when many mites are feeding on each grass plant will you observe damage. Mite numbers are usually kept in check by insects and predatory mites. Sometimes the predator population is absent, reduced by insecticides or not numerous enough to keep the pest mites in check.# Scales. Scale insects (see illustration on page 125) are mobile only in the young, immature stages. After that, they settle in a location on the leaf or stem, feed with needle-like mouth parts and usually cover themselves with an armored or shell-like protective covering. These tiny, globular or oval insects are easily overlooked when you examine turf.Two species of scale insects feed on turfgrass leaves: Rhodesgrass scale and bermudagrass scale. The Rhodesgrass
scale is found in the Gulf states and other southern states toward California. It attacks turfgrass crowns causing
infested plants to wither and die. The Bermudagrass scale infests bermudagrass, especially in shady areas.Both scale insects begin as nymphs, or crawlers, that move around on the plants before constructing their armored or shell-like covering. The covering of the Rhodesgrass
scale is dark purplish-brown with full-grown insects about 0.125 inch in diameter. Bermudagrass scales are white when mature and 0.06 inch long. Infested crowns have a moldy appearance. When numerous, scale insects produce dead areas in turf, especially in the shade. Detection is difficult because of their small size and lack of activity on the crowns of turfgrass. ORNAMENTAL PESTSInsect pests of ornamentals often are host-specific, and larval stages (which often are not highly mobile) usually
remain on the host as they develop. Therefore, accurate
plant identification is an important part of diagnosing
insect problems. As we mentioned earlier, insects possess either biting/chewing mouth parts or sucking/piercing mouth parts. Let’s look at important examples of each.• Chewing insects. Most damaging chewing insects are the larval stages of insects. Beetles, butterflies and moths, grasshoppers and related insects, and wasps feed on fo(
Left, clockwise) Dogwood twig borer, flatheaded apple borer, bark beetles’ feeding galleries and pine bark beetle.
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liage during their immature stages, and, in some cases, as adults as well. Roots also are commonly attacked.Leaf-feeding damage usually is quite easy to spot. Parts of leaves are chewed off, or in some cases, entire branches
are stripped bare. In other cases, insects feed on layers of leaf tissue without consuming the entire leaf. Thus, they leave thin leaf “skeletons” behind. Leaf miners leave peculiar trails or pockets in the leaf.Another common strategy of many leaf feeders is to live among the young leaves of a shoot tip, often binding them together with silk. Other caterpillars do this with older leaves as well, creating tunnels or nests in which to live. These are the leaf folders, leaf rollers and leaf tiers. Some caterpillars live in groups and build large webbed nests that are quite conspicuous. These are the tent caterpillars
and webworms.As this discussion shows, leaf feeders can leave a variety
of signs and include many types of insects. They all ultimately do the same thing: They consume foliage. Sometimes you will never find the feeding insect itself. Often this is because the damage was caused by a generalized
feeder, such as grasshoppers. These insects, unlike host-specific insects, are mobile and often feed and then move on. Thus, you see the damage but do not find the insect. This type of damage is often difficult to distinguish
from feeding due to caterpillars.• Sucking/piercing insects. This group includes aphids, scales, whiteflies and mites, among others. These pests cause damage different from that of chewing insects. On leaves, speckling is a common symptom. Each small, light-colored spot is a point at which the pest inserted its mouth parts and withdrew plant fluids. This is typical of mites and leafhoppers. Insects such as scales simply stay attached to one site, and so the insects themselves are what you’re likely to spot.Aside from foliar discolorations, sucking insects cause cupping, curling and other distortions of leaves and shoots. These result, in part, from toxins that the insects inject while feeding. Another sign of sucking insects is the growth of sooty mold. This fungus lives on honeydew excreted by sucking insects. Though unattractive, sooty mold is harmless to plants and is an excellent means of spotting infestations. The most serious damage of sucking
insects results from the withdrawal of sap. This can amount to a great proportion of the plant’s resources if pest populations are large. Lack of vigor and dieback often result.BEETLES (COLEOPTERA)As with turf, beetles pose some of the most serious problems for ornamentals. Often it is the larval (grub) stage that inflicts the most serious damage, but adults can be harmful as well. Damage includes foliar feeding, root feeding and wood boring, depending on the pest.# Japanese beetle. Japanese beetles (see illustration, page 121) were introduced into the United States early this century and have spread through much of the country since then. Both adult and grub stages cause damage to plants. The grubs are damaging to turf but also can harm ornamentals with their root feeding, especially on nursery
stock. However, adults cause extensive feeding damage
to flowers and foliage, and this is the most common reason ornamentals require treatment for Japanese beetles.
The most favored host is the rose, but numerous other ornamentals are subject to attack as well. The shiny green thorax and brown wing covers of Japanese beetles are distinctive.Foliar insecticides provide some protection from adult feeding, though repeat applications usually are necessary AphidsDogwood borer mothBagworm
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to protect newly emerging growth. One strategy is to reduce grub populations in nearby turf, which usually harbors the largest populations of developing Japanese beetle grubs. While this may reduce populations in the immediate area, it will not eliminate them entirely because
Japanese beetles are excellent fliers and will move in from other areas.# Leaf beetles. Leaf beetles (see illustration on page 125) include several species that consume the foliage of various
tree and shrub hosts. The larval stages do the most serious damage, but adults often feed as well. Leaf-beetle larvae have an appearance unlike that of caterpillars, appearing more like grubs (but usually more colorful). Feeding often leaves foliage skeletonized, and the larvae usually live in large groups for at least part of their development.
Elm leaf beetles are one of the more familiar leaf-beetle problems. Foliar or systemic insecticides are effective against leaf beetles.Many other leaf-feeding insects attack ornamentals in landscapes. Many caterpillars, unlike those discussed above, live solitary lives and do not create nests or produce highly visible damage. Often, the damage is not even noticed. When control measures become necessary, foliar insecticide sprays are almost always effective for foliar pests.# Root weevils. Root weevils include several species that attack a variety of woody ornamentals. The black vine weevil (see illustration on page 125) and the strawberry weevil are two of the most injurious species, feeding on broad-leaved evergreens (notably azaleas and rhododendrons)
and conifers (especially yews). The larvae feed on roots, causing severe damage that can lead to plant death. Also, the larvae sometimes feed on stems just above the soil surface, often girdling them completely. Affected plants frequently decline rapidly and die. This is often attributed to other causes because the damage can be inconspicuous. However, a close inspection of feeder roots and stems near the soil line usually reveals feeding damage if these insects are present. Feeding notches on foliage (from adult weevils) are another indication, but other, less-injurious weevils may be responsible. Foliar notching on Taxus (yews) is diagnostic of black vine weevils, however.Soil-applied insecticides control root-weevil larvae, while adults are susceptible to foliar applications. Even though adults do not inflict serious damage, controlling them reduces subsequent larval populations.# Borers and bark beetles. The larvae (grubs) of certain beetles that bore into the wood of trees and shrub are borers (see illustrations page 126). The adult beetles lay their eggs on the host plant. When they hatch, the larvae bore into wood, on which they feed, and cause decline and dieback of the affected plant. When they complete their larval stage (which may take one or several seasons, depending on the borer species), borers pupate within the host plant, eventually emerging as adults.Sawfly larvae WhitefliesUnarmored (cottony cushion) scales (left) and armored scales (right)
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Entrance holes, sawdust-like frass (droppings) on branches, swollen limbs and branch dieback are other typical symptoms of borers. If you cut into wood near entrance holes, you may be able to spot tunneling within the wood or perhaps the borer itself. The difficulty of treating borers is due to the protection they receive by living inside the wood of the host plant. Bark beetle grubs feed on tissue just inside the bark and on vascular tissue beneath it. The feeding usually occurs in interesting patterns—the larvae tunnel outward from main tunnels creating feeding galleries (see illustration, page 126). The gallery patterns are sometimes diagnostic. As the tissue underneath the bark dies, the bark may slough from the plant. Though a great many plants are vulnerable to many species of borers and bark beetles, the more common and serious pests include:• Dogwood borer• Shothole borer on cherries, peaches, plums and other trees• Elm bark beetles (which spread Dutch elm disease)• The bronze birch borer• The willow-and-poplar borer• The flatheaded appletree borer, which attacks many ornamental species• Pine bark beetles, which rapidly infest stressed pines.Traditional treatments consist of spraying insecticides on the bark of trunks and branches of susceptible species to provide a chemical barrier against newly hatched borers trying to gain entrance. This means you must time the applications to coincide with egg laying and hatch. Extension services sometimes announce treatment
windows based on borer hatch times, which often occur in spring or early summer. Products developed relatively recently provide control of some borers with parasitic nematodes. The advantage of these products is that they can provide control of borers even after they’re inside the plant. Thus, timing may not be so critical with these products, though control is not always consistent.
Pruning operations should take place at some time other than when prevalent borers are laying eggs. Apparently,
open wounds allow easy entrance for some borers and may even attract them. Many borers lay eggs in spring or early summer, which are not typical times to prune, so this should not constitute a major scheduling adjustment.Because borers are an ongoing threat, a good practice is to use non-host ornamentals. This avoids the need to treat every year for the same pest. Also, many borers and bark beetles detect stressed trees and attack them preferentially.
Thus, good cultural care also reduces infestations.
BUTTERFLIES AND MOTHS (LEPIDOPTERA)We are all familiar with the larvae of butterflies and moths—caterpillars. A huge number of species feed on plants, but relatively few become pest problems in landscapes.
Most cause noticeable damage with foliar feeding, though a few are wood borers.# Tent caterpillars and webworms. These caterpillars are the immature stages of moths and use silk to create nests. Several species have this habit, and host plants include a range of ornamental species. The most common of these pests include the Eastern and Western tent caterpillars and the fall webworm. The nests, which can be large and conspicuous, are not difficult to spot. However, careful inspection of trees that have been affected in past years may allow you to spot the caterpillars before their nests become too visible. Control is usually easy and effective with several insecticides, though occasionally nests are high up in tree crowns and you must use a forceful spray to reach them.# Bagworms. Bagworms (see illustration on page 127) are common pests in large parts of the country, especially
the Eastern half. They feed on well over 100 species
of plants, including both broadleaf and coniferous types. Bagworm damage consists of foliage consumption,
though the familiar “bags” can be unattractive. Bagworm caterpillars live inside these structures throughout their development. These pests can build up high numbers on individual plants because the females
cannot fly and must lay their eggs on the same plant. On isolated plants, it sometimes is practical to simply pick bagworms off by hand. They are so conspicuous, it’s hard not to spot them. If this is not practical, several insecticidal products provide adequate control with foliar sprays.A highly magnified mite with mite eggs
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# Cutworms. Cutworms (see illustration, page 123) are the larvae of several moth species. These caterpillars spend most of their time in burrows underground and emerge at night to feed on plants. Although the caterpillars
consume leaves and flowers, they also have the habit of chewing through stems at or near the surface, often severing the plant entirely. Thus, they destroy far more than they actually consume, making even small populations destructive to herbaceous plantings. Because cutworms feed at night, they are seldom seen. However, plants with severed stems lying on the ground or wilting plants that show stem damage near the ground are telltale signs of cutworms. Foliar applications of insecticides or granular baits are the customary control measures.# Borers. The larvae (caterpillars) of certain moths invade shoots, branches and trunks of trees and shrubs. Damage and symptoms are essentially the same as those of beetle borers—as are treatment strategies—though you should identify the specific pest and obtain appropriate treatment information. A significant wood-boring pest is the lilac borer (or banded clearwing ash borer—they’re the same species of moth) which attacks lilac, ash and other members
of the ash family. This insect often leaves pupal cases protruding from exit holes in the trunk when the adults emerge. Another serious pest is the dogwood borer (see illustration, page 127), also a clearwing moth.APHIDS, SCALES, WHITEFLIES (HOMOPTERA)This group of insects contains a large number of plant pests, including some of the most damaging and difficult-to-control insects. All possess sucking/piercing mouth parts. The serious pests in this group often build to enormous populations that withdraw large amounts of plant fluids, seriously degrading plant vigor.# Aphids. Aphids (see illustration page 127) are some of the most-recognized plant pests. They are small, soft-bodied insects that may or may not possess wings. Some species have woolly or waxy surfaces. A large number of species exist, attacking nearly every kind of plant. They pierce soft leaf, stem or flower tissue and feed on plant sap. Cupping, curling and other growth distortions are common symptoms of leaves and shoots. Aphids may be visible on young shoots, but they often reside on the undersides of leaves, as well. Some aphids even feed on roots, but aboveground infestations are those which most often require treatment.Much has been made of biological controls for aphids—parasitic wasps, ladybugs, lacewings—and these are effective
in many cases. However, aphids often are able to build to damaging populations in spring or summer before predators can increase to effective levels. Thus, chemical control measures may be necessary. Because aphids often prefer to feed on succulent young shoots, repeat applications may be necessary to protect new growth during growth flushes. Systemic insecticides are useful against aphids.# Scales. Scale insects (see illustrations on page 125) are some of the most difficult-to-control pests. They actually are soft-bodied insects, but the hard covering many species
possess provides good protection. These types are called armored scales. Other types lack hard coverings and, therefore, are called unarmored or soft. Several other families
are of importance and include mealybugs and cottony cushion scales. Altogether, a great many species occur, and most plants are susceptible to some type of scale. Scales anchor themselves to stems and leaves (or even bark) and suck plant fluids. Because they are essentially immobile, armored scales effectively seal themselves off for protection beneath their hard coverings. This is why they can be so difficult to control. Fortunately, scale parasites offer good natural control of many scales. When they do not, scales can cause extensive damage to plants. A side-effect of scale infestations is the secretion of honeydew,
which then gives rise to sooty mold on leaf surfaces. The occurrence of this is a good sign that scales (or other sucking insects) have infested a plant.The stage most vulnerable to control measures is the crawler stage. Crawlers are immature scales that move to new feeding sites. When they find a suitable site, they settle down and assume the typical scale lifestyle. Until then, they do not possess a protective covering and so are more susceptible to pesticides. Unfortunately, the crawler stage does not last long, so timing is critical and sometimes difficult to gauge accurately. Extension services
sometimes announce applications windows, and pheromones also are available as monitoring tools.Another option applicators use is spray oil (sometimes mixed with a pesticide), which is useful against some scales. Effectiveness depends completely on the degree of coverage, so high-volume applications are typical of oil applications for scales.# Whiteflies. Whiteflies (see illustration page 128) cause symptoms similar to aphids, to which they are related. Several species are of some importance, but the greenhouse
whitefly is the most important. It attacks many plant species, including outdoor landscape ornamentals. Whiteflies are small insects but easily visible to the naked eye. The adults are winged, but the immature stages—found on the undersides of leaves—resemble small scale
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insects. Various whitefly species attack a great many plant hosts by piercing soft plant tissue and sucking plant sap. This causes curling and cupping of leaves. Further, whitefly
infestations often produce copious amounts of honeydew,
which causes sooty-mold growth and creates a nuisance for cars parked underneath infested trees.Persistent control measures are necessary for whiteflies, and even then control may not be adequate. Adult whiteflies
are good fliers and spread rapidly, often re-infesting treated sites from nearby areas. In some regions, the deliberate introduction of parasites has dramatically reduced
whitefly problems.WASPS, BEES AND ANTS(HYMEN OPTERA)Most members of this group are considered beneficial, because they prey on other insects. However, several species can cause problems for the landscape manager.# Sawflies. Several kinds of sawflies (see illustrationona page 128) are pests of ornamentals. Sawflies, though they look like caterpillars, are the larval stages of wasps. Often, their posterior ends are curled in a peculiar fashion. Sawflies feed on numerous plant hosts, but each species usually is specific to one or a few types. Birch, pine and rose are some of the more commonly attacked ornamentals.
Several foliar insecticides control sawflies. However, you often can pick off limited infestations by hand because the larvae often congregate in dense masses that are easy to clip out and discard.# Ants. Ants seldom consume plants directly, but they still can become serious pests in landscapes. Some ants are known to farm aphids, moving them around to different
plants and providing them with some protection from natural enemies. Of course, many people consider ants a “nuisance” pest, which they certainly can be.Fire ants are a more serious problem because of the serious reaction people have to their stings, and their mounds can become quite large and disruptive in turf and shrub areas. Several products are formulated specifically
for fire-ant control.Carpenter ants nest in tree trunks. They do not actually consume wood for food. They simply hollow out spaces for the use of the ant colony. Some colonies become large enough to weaken trunks or large branches, creating hazardous trees.MITES# Mites. Mites (see illustration on page 129) pose serious control challenges to landscape managers. These tiny creatures live on leaf surfaces (usually the undersides). They also commonly create webbing that may be conspicuous
when infestations are heavy. Initially, it often is easier to spot the feeding damage than to find the mites themselves. Mites often cause spotting or speckling on leaves that is visible on the upper leaf surfaces. These mark the points where mites have pierced the leaf tissue to feed and should prompt you to inspect the leaves closely. Though tiny, most mites are visible to the naked eye. A 10x or 20x magnifier is a great aid, however. On some plants, conifers for example, feeding may not be noticeable as such. Look for browning and tip dieback, as well as webbing. Other symptoms, depending on the plant, may include purpling, leaf cupping or curling and leaf death. A method some use to inspect for mites is to hold a sheet of white paper beneath a shoot and strike or shake it. If mites are present, some will fall onto the paper, where you can see them crawling around.If certain plants have a history of mite infestation, monitor them closely—you’ll want to take control measures
before populations become heavy. Mites are notorious
for rapidly rebounding from control applications. The key to successful mite control is to repeat applications 7 to 10 days after the first one. This way, you’ll kill mites that hatch from eggs laid before the first application (most miticides do not kill the eggs). Complete coverage, especially
on the undersides of leaves is essential. Mites reproduce
rapidly, so they are able to develop resistance to pesticides relatively easily. Thus, it is important to rotate chemicals when you must make repeat applications for mites.Mites typically thrive in hot weather. Thus, damage tends to show during summer. Dusty conditions also seem to encourage mites, so dust-control measures sometimes
reduce mite populations.SNAILS AND SLUGSThese familiar pests feed on foliage of many ornamental
species, though they clearly prefer some plants over others. When populations are high, serious damage can result. The shiny slime trails snails and slugs leave behind are the surest way to distinguish their feeding from that of other pests. Although several home remedies have long been used—such as beer in a pan or salt granules—
pesticidal baits are very effective and fairly inexpensive.
CONTROLING PESTSThe most important part of controlling pests in landscapes
is to provide proper cultural practices for the plants growing there, whether they be turfgrasses or ornamentals.
Some insects (for example, pine bark beetles or bronze birch borers) are noted for their ability to detect stressed plants, which are less able to resist attacks. In
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addition, vigorous plants tolerate higher levels of pests without showing serious symptoms (for example, grubs in turf) and more rapidly outgrow damage that does occur. Proper cultural care does not mean that pest problems
will disappear, but in general, they should be less frequent and less severe when plants are healthy.A range of control products and techniques exists for controlling infestations. Your choice will depend on the pest, the host plant and other site factors. Many pests can be tolerated at low levels, from which only minor damage
will result. It is the large populations that require attention. Predators are a vital part of pest control in landscapes, but natural control obviously is not sufficient if damaging outbreaks are occurring. Thus, chemical controls also are a necessary part of maintaining landscapes
in acceptable condition. In some cases, introducing predators can substitute for chemical controls. However, this should be thought of as longer-term solution—if immediate control is needed, chemicals often are the only effective option.Providing good cultural care, encouraging natural predators, using plant species not preferred by prevalent insect pests and judicious chemical applications are all aspects of integrated pest management (IPM). All the aspects of IPM are important for maintaining healthy landscapes and making efficient use of available resources.Insects come into contact with insecticides in various ways. Contact insecticides are applied as sprays to surfaces,
usually foliage, where the target pests reside. Often, it is enough for the insect simply to walk across the treated surface and contact the insecticide with its feet. Leaf-feeding insects ingest foliar-applied chemicals when they feed on treated leaves; this is a typical means of control for many chewing insects. Soil-inhabiting insects contact the pesticide when it is washed down into the soil after an irrigation.Piercing-sucking insects, thought they are susceptible to contact products when directly contacted by them, do not consume foliage, so they do not ingest contact products.
However, several insecticides have systemic qualities,
meaning that plants take the chemical into their tissues. When sucking insects feed on sap, they also ingest some of the insecticide with it. Thus, systemic products are especially useful for pests such as aphids, mites, whiteflies and some scales.Granular formulations are effective for treating soil TURF PESTS(in order of apperance in text)Common nameScientific nameJapanese beetlePopillia japonicaEuropean chaferRhizotrogus najalisMole crickets Northern mole cricketsScapteriscus spp. Neocurtilla hexadactylaWirewormFamily ElateridaeBillbugs-sceral speciesSphenophorus spp.Black turfgrass AtaeniusAtaenius spretulusGround PearlsMaragarodes spp.Southern chinch bug Hairy chinch bugBlissus Insularis B. IeucopterusVagabond webwormSilver-striped webwormBluegrass webwormTropical sod webwormLawn sod webwormCrambus vulgivagellus C. predectillus Parapediasia teterella Herpetogramma phaeopteralis Pediasia trisectusBlack cutworm Variegated cutwormBronzed cutwormAgriotis ipsilon Peridroma saucia Nephelodes niniansArmyworm Pseudoletia unipunctaOat-bird cherry aphid GreenbugRhopalosiphum padi Schizaphus graminumSpider mites Bermudagrass mite Clover miteTetranychus spp.Eriophyes cynodoniensis Bryobia praetiosa Rhodesgrass scale Bermudagrass scaleAntonina graminis Odonaspis ruthae
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ORNAMENTAL PESTS(in order of apperance in text)Common nameScientific nameJapanese beetlePopillia japonicaElm leaf beetleXanthogaleruca luteolaBlack vine weevilStrawberry vine weevilOtiorthynchus sulcatusO. ovatusDogwood borer (beetle)Oberaea tripunctataShothole borerScolytus rugulosusAmerican elm bark beetleEuropean elm bark beelteHylurgopinus rufipesScolytus nultistriatusBronze birch borerAgrilus anxiusPoplar-willow borwerCryptorhynchus lapathiFlatheaded appletree borerChrysosbothris femorataPine bark beetles-many genera\speciesIps. Dendroctonus and Pityofenes spp.Bag wormsThyridopteryx ephemeraeformis Oiketicus spp.Fall webwormHyphantria cineaEastern tent caterpillarWestern tent caterpillarMalacosoma americanum M. californicumDogwood borer (moth) Synanthedon scitulaAphids-severalgenera\speciesFamily AphididaeUnarmored scales-several genera\speciesFamily Coccidae Mealybugs-several genera\speciesFamily PseudococcidaeArmored scales-severalgenera\speciesFamily DiaspididaeGreenhuse whiteflyTrialeurodes vaporariorumSawflies-pineSawflies-othersFamily Diprionidae Family TenthredinidaeImported fire antSolenopsis invictaCarpenter antsCamponotus spp.Mites-severalgenera\speciesAcarina-family Tetranychidaeinsects, especially in turf. These must be irrigated to wash them into the soil where they can contact soil-inhabiting pests. In some cases, granular insecticides, after being irrigated into the soil, are taken up by the plants, which then gain systemic protection from the product.Recently, soil or trunk-injected systemic insecticides have become a more popular means of treating trees. The advantages of their over traditional sprays are obvious and provide a level of control not usually possible with sprays on large trees.Baits are useful for mobile insects, insects that do not reside on the host plant (cutworms, for example) and other pests such as slugs and snails. Using baits that attract
these pests is more efficient than spraying an entire landscape just to ensure the pest ingests some insecticide.
Horticultural oils are not traditional insecticides. They work by literally suffocating
insects. Thus, complete coverage
is essential for good control with oils. In hot weather, some oils pose a risk of burning foliage, so this type of application
is best suited to winter and spring applications for many oil products.
Winter-applied oil treatments are referred to as dormant
sprays and control insects overwintering
on the plant.Insect growth regulators (IGRs) are a relatively recent development in pest control but show much promise. These chemicals mimic natural hormones
that control the life cycle of insects
and interrupt the normal development
already have introduced a few IGR products, and more are being developed for both turf and ornamental uses. IGRs are highly specific to the target pest, so their use does not harm predator populations.Predators and parasites are used successfully by many landscape managers. Unfortunately, many customers demand more immediate results than predators can offer. When they fit into a pest-control program, however, predators can cost-effectively and successfully control a number of pests. Parasitic nematodes, wasps and flies—as well as predatory insects such as ladybugs, lacewings and mantids—are available from suppliers. Much more remains to be learned about using natural controls in turf and ornamental sites, so this is an actively evolving field.TLD