Chapter 25 Maintaining landscape plants.
Upon completion of this chapter, you should be able to
* water, fertilize, edge, and mulch tree and shrub plantings
* prune trees and shrubs correctly
* maintain annual and perennial flower plantings
Sustained Care of Plantings
As important as the design and proper installation of landscape plantings is their ongoing maintenance. Many gardens do not attain the appearance envisioned by the landscape designer until the plants have time to mature. Aiding those plants in their healthy maturation requires attentive and knowledgeable maintenance. Also, some designs require specific plant effects such as clipped formal hedges or espalier training to create the garden as envisioned. In both instances, the value of skillful landscape maintenance is apparent. A maintenance program generally will include the following tasks: watering, fertilizing, mulching, edging, pruning, pest control, and winterization.
Depending on the region of the country, supplemental watering may be an infrequent task or so regular that it requires an automatic irrigation system. The need for a good water supply to the plantings has been discussed in earlier chapters. Here the subject is the objectives of proper watering, its frequency, and its quantity.
Initially, watering must promote deep root development by the plant to establish it securely in its location. Later, watering must keep the plant healthy and growing actively even during dry summer weather. Much winter damage to evergreens can be avoided if the plants are kept well-watered throughout the summer and autumn.
Not all plants require the same amounts of water. Neither will all plant root systems grow to the same depth in the soil. While nearly all landscape trees and shrubs will die if kept too long in either arid or waterlogged soil, certain species are especially sensitive to sites that are too dry or too wet.
Infrequent and deep watering is preferable to frequent, shallow water. Enough water should be applied to wet the soil to a depth of 12 to 16 inches. In the Southeast and Southwest, supplemental water may be required nearly every day. In other regions, supplemental watering may be weekly or even less frequent.
Trees will grow without fertilization in most soils once they are established. However, they will grow with greater health and vigor if they are fertilized annually. Shrubs will respond to proper fertilization with lush growth, greater resistance to pests, and less winter damage.
For shrubs growing in cultivated beds, fertilizer may be applied in early spring. Depending on the plants involved, each 100 square feet of bed area should receive between one and three pounds of a low-analysis, complete fertilizer. The fertilizer should be distributed uniformly over the soil beneath the shrubs, with most of the fertilizer under the outer edge of the shrub where the fibrous roots that absorb the nutrients are located. The fertilizer should not be allowed to touch the foliage, or foliar burn (a reaction to the chemicals) may result. If the soil is dry, the fertilizer should be worked into the soil with a hoe. If the weather has not been abnormally dry, the fertilizer can be left untilled, and the next rainfall or irrigation will wash it into the soil.
Trees are fertilized in different ways depending on the species, the age of the plant, the adjacent plants and terrain, and the equipment available to do the job. Small trees may be fertilized to promote their growth and ensure their health. Mature trees may be fertilized to sustain their health but with no concern for size expansion. Where trees stand in open lawn areas, fertilizer can be applied to the surface using the same spreader that would be used for lawn fertilization. In settings where trees are crowded by structures or other plants, or are on sloped terrain where runoff would prevent movement into the soil, fertilization may be by direct incorporation into the soil or directly into the tree. With only a few exceptions, the method used makes no difference in the trees' reaction. As long as the fertilization provides a correctly balanced nutritional supplement, the delivery system is not significant.
Most important is delivering the fertilizer where it can be taken up by the tree. The take-up of nutrients by trees occurs at the outer extremes of the root zone and within the top 6 to 8 inches of the soil. The outer edge of the root zone in established trees was long believed to correspond to the edge of the foliage canopy, termed the drip line. Recent knowledge indicates that tree root systems commonly extend far beyond the drip line. Therefore, placing fertilizer close to the trunk or limiting its application just to the drip line may miss the most absorbent roots entirely.
If fertilizer is being applied to the soil in holes drilled with augers or by injections made with high pressure hydraulic sprayers (Figure 25-1), the holes or injections should extend from halfway between the trunk and drip line to a point approximately a quarter of the radius outside the drip line. Drilled holes are best for dry fertilizer application. They should be 6 to 8 inches deep and spaced 18 to 24 inches apart throughout the zone of application. A dry mixture of 50 percent high analysis, complete fertilizer and 50 percent sand as a carrier, is poured into the holes.
[FIGURE 25-1 OMITTED]
High-pressure injection uses concentrated liquid fertilizers. The spacing is greater than for dry applications, with the objective being to apply about a gallon of fertilizer with each injection and enough injections to deliver approximately 200 gallons of fertilizer within each 1,000 square feet of the zone of application.
Direct application of nutrients into a tree's vascular system is possible using the same technology as that used to apply systemic pesticides (see Chapter 26). However, from a purely practical standpoint, it is only of relevance when a tree is in need of micronutrients that are unavailable to the tree for specific reasons such as local soil conditions.
The one most common mistake in the fertilization of landscape plants is the application of fertilizer too late in the growing season. The result is often a flush of vegetative growth in response to the nitrogen that leaves the plant ill-prepared for winter. Great damage can result to plants from well-meaning but ill-timed fertilization.
The objectives, advantages, and disadvantages of mulching, and examples of commonly available products were outlined in Chapter 20. For extended maintenance of landscape plantings, mulches require replacement. Organic mulches decompose, forming humus and an ideal medium for the germination of newly deposited weed seeds unless mulch is replaced annually. Inorganic mulches do not decompose but decline in appearance if not freshened periodically. Caution: Old mulch should be removed before new is added. Otherwise, the soil level over the roots is gradually deepened and the plants may die. Also, to reduce the possibility of stem and trunk tissue being killed by the heat of decomposing mulch or by bacterial and fungal infection promoted by the moist mulch, the mulch should not be piled against the trunk or crown. It should be kept 3 to 5 inches back from shrub crowns and the trunks of young trees. Older trees need at least 8 to 12 inches of mulch-free area.
One important use of mulch is as a protective divider to prevent lawn mower damage to the base of plants, Figure 25-2. A gouge from a lawn mower creates a site for pathogen or insect invasion of the plant. If hit repeatedly, a tree may become partially or completely girdled. In large landscapes with numerous trees and an understaffed maintenance crew who rely on riding mowers for grass cutting, frequent injury to trees results from attempts to mow as close as possible, thereby eliminating hand trimming. A ring of mulch around the base of each tree can protect the tree, speed the overall mowing time, and create a neat appearance, Figure 25-3.
[FIGURE 25-2 OMITTED]
[FIGURE 25-3 OMITTED]
The term edging has a double use. As a verb, edging refers to cutting a sharp line of separation, usually between a planting and the adjacent lawn. Reference may be made to edging a bed or edging the lawn along a walk. The term can also be used to describe a product, usually a steel or plastic strip that can be installed as a physical separator between planting beds and lawns or between lawns and paved areas.
To edge a bed requires an edging tool or a flat-back spade. The edger or spade is dug into the ground to a depth of 6 to 8 inches and a wedge of sod removed, Figure 25-4. The process continues along the edge of the bed or the paved area. Cutting through the sod sharply and vertically discourages the roots of the turf from growing into the bed. If the landscape is large, edging can be accelerated by using a power edger.
The installation of edging material against the cut edge further discourages the horizontal spread of grass roots into the bed. It also retains a sharp turf line along walks and drives. The best edging materials are firm, not easily bent and crushed. The corrugated foil edging promoted to the home garden market is not satisfactory for professional use and should be avoided. Heavy-gauged steel and polyvinyl-chloride edging is available from numerous manufacturers. Satisfactory edges can also be created with wood, bricks, and other modular manufactured materials.
In regions where winter heaving of the soil is common, it is best to select an edging material that can be anchored, Figure 25-5. Most anchoring techniques are only moderately effective, however, and resetting heaved edging is a common spring activity in northern landscapes. It is worth the effort, considering the advantages that the material offers in retention of the bedline and separation of the mulch from the lawn mower.
Chapter 26 deals with plant pests, the symptoms of disease and injury that they create, and the principles used to control them. Emphasis is given to the decisions that a landscaper or arborist must make to apply the knowledge of pest control to the maintenance and management of a landscape site. It becomes a three-part judgment call: What is the potential or actual extent of pest damage? What is the quality expectation and/or tolerance level of the client? What are the environmental ramifications of the proposed method of control?
Whether a professional landscaper or arborist, a property manager, or a home gardener answers the questions, they must be answered. In many cases, the control methods used will be restricted or guided by local laws and regulations. Many states and communities ban or restrict the use of certain pesticides or limit the right to apply them to registered pesticide applicators. Those that are available for general purchase are increasingly limited and have diluted concentrations.
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Every state has a college of agriculture that is responsible for approving the use of every pesticide used within the state. Scientists at the colleges are also responsible for determining the appropriate product and formulation for use against a particular disease, weed, or insect on a particular host at a particular time of year or stage of development. It is increasingly probable that their recommendations will incorporate the latest biological control measures. Their recommendations are updated and published each year for use by the states' professionals. Copies of the recommendations are available directly from the state universities and often from local Cooperative Extension offices. Everyone who uses pesticides must realize that although pest problems may be similar in different states and in different regions within a single state, the environmental conditions can vary in subtle ways not always apparent.
Therefore, if a pesticide is not approved for use within a state or region, it is dangerous, unethical, and illegal to purchase the product elsewhere and apply it in the restricted zone. It is also equally dangerous and illegal to increase the dosage or frequency of application beyond that which is recommended.
Managing the landscape in a manner that optimizes plant health is the best way to control pests. Avoiding the use of plants in locations that do not fit their cultural needs will also avoid the costs of labor and materials needed to control the predictable invasion of weeds that will flourish in those locations or the insects and diseases that will find their way to the weakened plants placed in unsuitable locations.
Regular scouting of the landscape to monitor the presence, numbers, and stage of development of pests is another mandatory management task in order to determine what controls are needed, where they are needed, and when to apply them for maximum effectiveness.
Pruning Trees and Shrubs
Pruning is the removal of a portion of a plant to improve its appearance and health and to control its growth and shape. It is easily done, but not so easily done correctly. Each time a bud or branch is removed from a plant, it has a short-term and long-term effect. The short-term effect is the way the plant looks immediately after pruning, and perhaps through the remainder of the growing season. The long-term effect is the way the plant appears after several seasons of growth without the part that has been pruned.
Landscape pruning tools are available in a range of sizes and qualities. Whether a hand tool or power tool, all pruning tools share a common attribute: they are sharp and must be used carefully with a vigilant regard for the safety of the user and others nearby. The tools used by home gardeners, landscape professionals, and aborists include:
* Hand pruners--Hand pruners are used to cut branches up to about 1/4 inch in diameter. There are two styles in use. One is like a pair of scissors in that it has two sharpened edges (a blade and a curved anvil). The other style has one sharpened blade and a flat, straight anvil that it cuts against. Professional horticulturists generally prefer the scissor-type hand pruner because it gives a more precise cut and is less likely to damage the plant tissue by squeezing against an unsharpened anvil.
* Lopper pruners--Also available as scissor or straight anvil types, loppers are used to cut branches having diameters up to about 1/2 inch. Loppers have longer handles than hand pruners. That allows the user greater leverage and extended reach. It also can result in damage to the tool and the plant if the long handles are used to twist off a partially cut branch. If the loppers cannot make a quick, clean cut through a branch, a pruning saw should be used instead.
* Hedge shears--These are the most task-specific of all pruning tools. They are used to shear and shape hedges, with some secondary applicability to the shearing of plants used in formal settings. Hedge shears are available as a scissor-like hand tool or as a wand-like power tool.
* Hand pruning saw--When a branch exceeds 1/2 inch in diameter, it is important to use a saw, not a hand pruner or lopper. Pruning saws are designed to cut live wood, unlike carpenter saws that are made for dried wood. Hand pruning saws with straight blades cut best when pushed away from the user. Curved blade saws cut best when pulled toward the user. The circumstances of use will usually dictate the proper choice of saw.
* Pole saw--This tool is simply a hand pruning saw or a lopper with a long handle. It permits the user to reach up into a tree for the removal of the same sized branches that are removed at lower levels with regular handsaws or loppers. Caution: It is difficult to see electric wires that may be in the canopy of trees. Do not cut until you are certain of what is being severed.
* Chainsaw--This is a very dangerous tool! It may be powered by gasoline or electricity and is used to remove branches that cannot be cut with the hand tools described. Razor sharp teeth attached to a chain cut through the wood. Protective clothing and a thorough knowledge of all safety measures regarding the use and maintenance of the chainsaw are essential.
* Other power pruners--Professional landscapers and arborists have available an expanded assortment of tools that do the same tasks described for the hand tools but have the benefits of engine power to increase their strength and cut size capability. Powered forms of pole pruners and loppers are available. These, too, are highly dangerous to use.
Parts of a Tree
The following parts of a tree are important for an understanding of proper tree pruning, Figure 25-6. The lead branch of a tree is its most important branch. It is dominant over the other branches called the scaffold branches. The lead branch usually cannot be removed without destroying the distinctive shape of the tree. This is especially true in young trees.
The scaffold branches create the canopy, or foliage, of the tree. The amount of shade cast by the canopy is directly related to the number of scaffold branches and the size of the leaves. When it becomes necessary to remove a branch from a tree, removal usually occurs at a crotch, the point at which a branch meets the trunk of the tree or another, larger branch.
It is always desirable to leave the strongest branches and remove the weakest. Where the crotch union is wide (approaching a right angle), the branch is strong because there has been no crowding and pinching of the new wood produced each year by the trunk and branches as they expand. Where the crotch union is narrow, the branch is weak due to a pinch point forming where the expanding trunk meets the expanding branch, Figure 25-7. Growth in that area becomes compressed and dwarfed, and the branch may snap off at that point during a heavy wind or in response to the weight of a person climbing on it.
[FIGURE 25-6 OMITTED]
Two other types of branches often found on trees are suckers and water sprouts. Suckers originate from the underground root system. Water sprouts develop along the trunk and branches of a tree. Neither is desirable for an attractive tree, and both should be removed.
Parts of a Shrub
A shrub is a multistemmed plant, Figure 25-8. Its branches and twigs differ in age, with the best flower and fruit production usually on the younger branches. The younger branches are usually distinguished by a lighter color, thinner bark, and smaller diameter. The point at which the branches and the root system of a shrub meet is the crown. New branches originate at the crown, causing the shrub to grow wider. New shoots may arise from existing roots or from prostrate stems, termed stolons, to create new shrubs from the parent plant. In some grafted plants, the graft union may be seen at or near the crown. Shoots originating from the stock (or root portion) of a grafted plant are cut away since the quality of their flowers, fruit, and foliage is inferior. Only shoots originating from the scion (or shoot portion) are allowed to develop.
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[FIGURE 25-8 OMITTED]
The Proper Time to Prune
Landscapers who design and install as well as maintain landscapes usually prefer to prune when they have little other work. This distributes their work and income more evenly throughout the year. Some plants can accept this off-season attention and remain unaffected by it. Other species accept pruning only during certain periods of the year.
There are advantages and disadvantages to pruning in every season. Since seasons vary greatly from region to region, the following can be used only as a general guide to the timing of pruning.
Winter Pruning. Winter pruning gives the landscaper off-season work. It also allows a view of the plant unblocked by foliage. Broken branches are easily seen, as are older and crossed branches. The major disadvantage of winter pruning is that without foliage it is difficult to detect dead branches. Because of this, plants can become seriously misshapen if the wrong branches are removed. An additional disadvantage is the damage that can be done through cracking frozen plant parts.
Summer Pruning. Summer pruning also provides work during a slower season for the landscaper. An advantage of summer pruning is that it allows time for all but very large wounds to heal before the arrival of winter. The major limitation of summer pruning is that problems of plants may be concealed by their full foliage. Branches that should be removed are often difficult to see. Especially with trees, it is difficult to shape the branching pattern unless all the limbs are visible.
Autumn Pruning. Pruning during the autumn season may conflict with more profitable tasks for the landscaper. In terms of the health of the plant, autumn pruning is acceptable as long as it is done early enough to allow cuts to heal before winter. Autumn pruning should not be attempted on plants that bloom very early in the spring, however. These early bloomers produce their flower buds the preceding fall. Thus, fall pruning cuts away the flower buds and destroys the spring show. Autumn pruning should be reserved for plants that bloom in late spring or summer, producing their buds in the spring of the year.
Spring Pruning. Since spring is the major planting season, most landscapers do not welcome pruning requests unless maintenance is their principal business. However, most plants are most successfully pruned during the spring. As buds begin to swell, giving evidence of life, it is clear which are the live and dead branches. Furthermore, there is little foliage to block the view of the complete plant. Spring pruning provides the plant with maximum time for wounds to heal. In addition, the unfolding leaves conceal the fresh cuts from the viewer's eye.
If the plant is an early spring bloomer, it is best to prune it immediately after flowering. Plants that have a high sap pressure in the early spring, such as maples, birches, walnut, and poinsettias, should not be pruned until summer or fall, when the sap pressure is lower. Otherwise, the excessive exudation becomes unsightly.
Parts of the Plant to Prune
The reason for pruning will determine the limbs and branches to be removed from a tree or shrub. If the objective is to remove diseased portions, the cut should be made through healthy wood between the trunk or crowns and the infected part (Figure 25-9). The cut should never be made through the diseased wood or very close to it. This contaminates the pruning tool, which may transmit the disease to healthy parts pruned later.
If the objective is to improve the overall health and appearance of the plant, branches growing into the center of the plant should be removed. Limbs and twigs that grow across other branches can crowd the plant and cause sites of infection to form by rubbing abrasions through the bark. If more than one limb originates at the tree crotch, the strongest should be left and the others removed, Figure 25-10. Major structural limbs and twigs must be left so that no holes appear in the plant. Often overlooked is the fact that many secondary branches can stem from one older branch. The removal of one branch from a young tree can result in an older tree missing an entire side.
[FIGURE 25-9 OMITTED]
If the purpose of the pruning is to create denser foliage, as with evergreens, the center shoot is shortened or removed. This encourages the lateral buds to grow and create two shoots where there had been only one, Figure 25-11.
The method of pruning a tree or shrub depends on the size and number of branches to be removed. Limbs are pruned from trees with a technique called jump-cutting. This method allows a scaffold limb to be removed without taking a long slice of bark with it when it falls. A jump-cut requires three cuts for the safe removal of a limb, Figure 2512. The final cut should remove the stub of the limb close to the trunk, but not directly against it. Until recently, the wound would then be covered with a wound paint to make it less conspicuous until the plant has time to heal. However, recent research has suggested that wound paints may actually delay healing of plant tissue. Where this is suspected, the landscaper should not use them.
When shrubs are pruned, one of two techniques is used. Thinning out is the removal of a shrub branch at or near the crown or its point of origin. It is the major means of removing old wood from a shrub while retaining the desired shape and size. Heading back is the shortening, rather than total removal, of a twig. It is a means of reducing the size of a shrub. In cases where shrubs have become tall and sparse, a combination of thinning out and heading back can rejuvenate an old planting, Figures 25-13 and 25-14.
In heading back, the location of the cut is important, Figure 25-15. If too much wood is left above the bud, the twig will die from the point of the cut back to the bud, but the cut may not heal quickly enough to prevent insect and pathogen entry. Also, the woody stub itself may decay later. A cut below the bud will cause the bud to dry out and possibly die. The cut should be made just above the bud and parallel to the direction in which the bud is pointing. The cut should be close enough to the living tissue to heal over quickly but not so close to the bud that it promotes drying. The direction in which the branch of a plant grows can be guided by good pruning techniques.
[FIGURE 25-10 OMITTED]
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Branches growing into the plant can be discouraged by the selection of an outward-pointing bud when heading back, Figure 25-16. If the twig has an opposite bud arrangement, the unnecessary one is removed.
[FIGURE 25-12 OMITTED]
How to Prune Hedges
The creation of a hedge requires close spacing of the shrubs at the time of planting and a special type of pruning. The landscaper must shear the plant so that it becomes as dense as possible. This is usually done with hedge shears. The hedge shears easily cut through the soft new growth of spring, the season when most hedges are pruned. For especially large hedges, electric or gasoline powered shears are available. However, practice and skill are required for the satisfactory use of power shears. Damage can occur quickly if the landscaper does not keep the shears under control.
[FIGURE 25-13 OMITTED]
[FIGURE 25-14 OMITTED]
[FIGURE 25-15 OMITTED]
A properly pruned hedge is level on top and tapered on the sides, Figure 25-17. It is important that sunlight be able to reach the lower portion of the hedge if it is to stay full. Otherwise it becomes leggy and top-heavy in appearance.
[FIGURE 25-16 OMITTED]
National Pruning Standard
Recent cooperation between members of the arborist, landscape, and nursery industries and governmental organizations has resulted in the development of national pruning standards. These standards are known as the American National Standards Institute (ANSI) Standards and seek to establish a level of acceptable performance for all professionals engaged in the care of woody plants.
No components of the landscape require more maintenance time than flower plantings. This is why landscapes with a low budget for maintenance must minimize the use of flowers. Reasons for the high maintenance costs are that:
* weeds must be pulled by hand or controlled with costly selective herbicides
* flowers are more susceptible to insects and diseases that mar their aesthetic appearance, therefore requiring additional expenditures for pesticides
* flowers tend to go to seed or get leggy with age if not pinched back frequently during the growing season (this subject is discussed later in the chapter)
* many perennials bloom only once a year but must be cared for throughout the growing season to ensure a good flower display the following year
* some perennials, notably the tender bulbs, must be dug up, put into storage for the winter, and set out again each spring
[FIGURE 25-17 OMITTED]
Several good herbicides are approved for use in flower plantings. If applied for preemergence and postemergence control, a weed-free flower planting can be attained. One danger of herbicides in flower beds is that the chemicals are always selective --that is, they kill grasses or broad-leaved weeds, but seldom both. Since flower plantings can have characteristics of both, damage can be done to some flowers even when others are uninjured.
Most herbicides used in flower plantings lose their effectiveness if the soil is disturbed after application. In such cases, landscapers must avoid cultivating the soil surface if they wish the full benefit of the herbicide.
All flowers should be watered frequently and deeply during dry periods. Their shallow roots quickly react to drought conditions, and they reach a critical wilting point much sooner than the woody plants of the landscape. Flowers planted beneath trees and shrubs must compete with the woody plants for surface water, and they will dry out faster than flowers not in such competitive locations.
Annuals can be fertilized in midsummer with a low-analysis fertilizer to keep them lush and healthy. Bulbs should be fertilized immediately after flowering with a high-phosphorus fertilizer such as bone meal. Nonbulbous perennials grow best if fertilized in the early spring. Summer or fall fertilization of perennials can harm the plants by keeping them too succulent as winter approaches.
Many summer annuals must be continually tended to remove dead flower blossoms, a practice termed dead-heading. Plants such as petunias and geraniums are especially demanding. Combining deadheading with routine maintenance can reduce labor costs.
Annuals are most likely to benefit from pinching back, but certain perennials such as hardy mums will also do better if pinched. Pinching removes the terminal shoot on each branch of the flower and allows the lateral shoots to develop, thereby creating a fuller plant. Soft pinching is done with the thumb and forefinger and removes the terminal bud or, at the most, the terminal and the first set of laterals. Hard pinching may shorten each stem by one third or more. Most flowers benefit by a hard pinch soon after being set out, followed by one or two soft pinches during the summer. With perennials such as mums, whose flower bud initiation is tied to a photoperiod response, the last pinch should not be after mid-July if a good flower display is to be seen in the autumn.
Flowers such as petunias or rose moss that are valued for their profuse blossoms, can be kept from getting leggy and going to seed by severely cutting them back about midsummer. A tool as indelicate as a pair of grass clippers can be used to provide a hard pinch if the planting is extensive. A period of several weeks with few flowers will follow until new reproductive growth begins. However, the fresh look and new flowers that result will carry the annuals right into the fall season.
A. From the choices given, select the answer that best completes each of the following statements.
1. The main objective when watering trees and shrubs is to--.
a. keep the humidity high
b. promote deep root development
c. keep the foliage clean and moist
d. prevent wilting
2. The proper time to fertilize shrubs is in --.
a. early spring
b. late summer
c. early fall
3. Trees should be fertilized --.
a. near their anchor roots
b. at the nursery before digging
c. near their base
d. beneath the drip line of the canopy
4. The purpose of edging a bed is to --.
a. divert surface water
b. discourage turf roots from entering the bed
c. hold the mulch within the bed
d. improve drainage
B. Answer each of the following questions as briefly as possible.
1. You discover a leaf spot disease on the English ivy plantings that are the major groundcover of a large landscape. How can you determine what control to use, what products to select, and when and how much to apply?
2. Complete the following statements.
a. Removing a portion of a plant for better appearance, improved health, controlled growth, or attainment of a desired shape is termed --.
b. The most important branch on a tree is the --.
c. Scaffold branches create -- of the tree.
d. The point at which a branch meets the trunk or a larger branch is termed the --.
e. Undesirable branches originating from the root system of a tree are termed --.
f. Undesirable branches originating from the trunk of a tree are termed --.
g. The point of a shrub at which the branches and root system meet is termed the --.
h. Generally, the younger branches in a shrub will have a -- color.
i. Shoots originating from the stock of a grafted plant are -- compared to those originating from the scion.
j. Flower and fruit production occur most profusely on -- branches.
3. Place Xs in the following chart to compare the advantages and disadvantages of pruning during different seasons.
4. Which three branches shown in this drawing should be removed, and why?
5. What is the difference between thinning out and heading back in the pruning of shrubs?
C. Write a short essay on the maintenance of flower plantings. Outline the care needed by both annuals and perennials to keep them healthy and attractive throughout the growing season. Assume the environmental conditions to be those in your own area.
Jack E. Ingels
State University of New York
College of Agriculture and Technology
Cobleskill, New York
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|Title Annotation:||SECTION 3 Landscape Maintenance|
|Publication:||Landscaping Principles and Practices, 6th ed.|
|Date:||Jan 1, 2004|
|Previous Article:||Chapter 24 Interior plantscaping.|
|Next Article:||Chapter 26 Plant injuries: identification and care.|