Printer Friendly

Chapter 17: ornamental trees, shrubs, and groundcovers.

KEY TERMS

arboretum arboriculture arborist focal point foundation plant specimen plant

Trees and shrubs add beauty to homes, cities, parks, highways, and schools. They provide natural beauty in the woods and wild areas that we wish to recreate in our immediate environment. Trees provide practical solutions in many situations. Some uses for trees are as follows:

* Windbreaks--reduce winter fuel consumption

* Reduce soil erosion, especially on slopes

* Clean the air and provide oxygen

* Increase property value, either for aesthetic reasons or by cash income for wood products

* Cool the air around them and provide shade

* Protect livestock from winds and sun

* Reduce sound from traffic and other noises

* Provide food and a home or shelter for many species of wildlife

* Provide a living snow fence

* Protect crops from damaging wind, improving crop yields

* Beautify homes, farms, public spaces, and roadsides

To maintain the beauty that woody plants can provide, it is important for us to understand how to select the proper plants for the situation and how to properly care for and maintain them.

Trees and shrubs comprise the two largest groups of woody plants. As a matter of fact, lignin, a component of the cell walls of plants, which is largely responsible for the strength and rigidity of trees and shrubs, is the most abundant organic matter on earth. Many vines (lianas) and groundcovers are also woody, and will be treated in this chapter as well.

Trees and shrubs provide the backbone for the landscape. Whether they are deciduous or evergreen, they provide structure and form throughout the year that many herbaceous plants cannot, particularly in temperate climates. Woody plants are ornamental in their shape, texture, and color and bring seasonal interest in the form of colorful bark, flowers, fruit, leaf color, and branch structure.

TREES: SHADE AND ORNAMENTAL

Some trees may grow as large as 100 feet or taller, whereas others mature at a height of only 5 or 6 feet. Some trees have showy flowers while the flowers on others are hardly noticeable. Larger trees often provide a lot of shade and homeowners appreciate them for this value. Smaller trees are appreciated for their ornamental qualities. Most of the small trees used for ornamental purposes have showy flowers, colorful foliage, an aesthetic framework or structure, or a combination of these. Large trees require large spaces that some homes lack. Such trees work well in public areas, such as parks and college campuses. Small trees complement a more intimate space such a small patio area or a mixed border. When selecting a shrub or tree for an area, be mindful of the space available and consider the mature size of the species before you buy it and plant it. Too often a large tree is planted under power lines or too close to a house or building, only to become a very costly mistake later when it must be removed or an ugly problem when it is pruned to avoid power lines (Figs. 17-1 to 17-4, see pages 425-427).

When used alone for its ornamental qualities, a tree is said to be a specimen plant (Fig. 17-5, see page 427). Trees that have showy flowers, unusual foliage or form will become a focal point (Figs. 17-6 to 17-9, see pages 428-429). For this reason, it is important to use care in selecting trees. Too many unusual trees in a small space can become distracting and chaotic rather than aesthetically pleasing. If you desire a grouping of unusual trees, then compose them as you would a picture, so that they complement rather than compete with each other.

Arborists are people whose job it is to monitor the health of trees and to care for them. Arboreta are places where a collection of trees and shrubs are cultivated for scientific or educational purposes. Arboriculture is the care and management of woody plants.

Trees may be deep-rooted or shallow-rooted and may therefore affect structures around them (Fig. 17-10, see page 430). Feeder roots are nonwoody roots concentrated near the soil surface. They are responsible for much of the oxygen, water, and nutrient uptake. Feeder roots normally die and are replaced on a regular basis. Some trees also have root hairs that are responsible for a great deal of nutrient and water uptake. Others, such as many evergreens, form a symbiotic association with a type of fungus called mychorrhizae that live on and in the feeder roots. Mychorrhizae do not harm the tree but aid in water and nutrient uptake. Rototilling under a tree may eventually kill the tree because of the destruction of important feeder roots, root hairs, and mychorrhizae.

Tree root structures vary greatly, depending on soil conditions and moisture availability as well as species. A thin layer of topsoil with heavy clay subsoil restricts root growth to close to the surface, whereas deeper topsoil permits deeper root penetration. In many trees, the root mass is concentrated in the top 12 to 24 inches of soil, in a circumference that exceeds the branch spread, or dripline, by 2 to 4 times its spread or even further (Fig. 17-11, see page 431). Some trees can develop deep taproots that can access water in the soil for 30 feet or more, given adequate drainage and absence of compaction. Table 17-1 (see page 432) lists trees with deep and shallow root systems. Trees with a strong taproot system will eventually slough off their taproot in maturity, which can occur 10 to 40 years later and develop a tiered root system, with feeder roots closer to the surface and sinker roots that permeate deeper layers in the soil. In restricted root environments, such as those present in many urban settings, tree root growth is more restricted than what occurs in forested or other natural, undisturbed areas. In urban areas, even trees that form tap roots or deep root systems may lack a deep tap root if growth is restricted by compaction, a high water table, or heavy soils. These conditions also result in most of the root system developing only 2 to 3 feet below the surface of the soil.

[FIGURE 17-1 OMITTED]

[FIGURE 17-2 OMITTED]

[FIGURE 17-3 OMITTED]

Tree roots can become injured if the soil around them is altered or compacted. Digging around a tree's roots and rototilling over them are sure ways to damage them and put the tree's health at risk. Adding soil over the tops of roots reduces oxygen and water availability and will be damaging to roots and trees as well. Professionals trained in the care of trees should be consulted if it is necessary to dig in the root zone of a tree. Special pruning techniques can sometimes compensate for the damage that will be caused by root zone damage. During construction, heavy equipment must be kept off the root system.

Lawn grasses compete with trees for nutrients and moisture, which can result in a droughty condition around tree roots. Grasses and trees have different fertilizer needs. Grasses are shallow-rooted and compete with trees for surface moisture. Finally, turfgrass species require sun for optimal growth. Even shade-loving species of fine fescue require some light and will not thrive in deep shade. For all these reasons, you may find it preferable to use mulch or another nonliving groundcover under trees. Irrigation of turf under trees during drought, especially in heavy soils that do not drain well, can result in a waterlogged root area that may lead to the demise of the tree.

[FIGURE 17-4 OMITTED]

[FIGURE 17-5 OMITTED]

[FIGURE 17-6 OMITTED]

[FIGURE 17-7 OMITTED]

SHRUBS

Shrubs may be utilitarian or ornamental, too. They are used for hedges or barriers, for screening, in mixed borders, as specimen plants, and as foundation plants (Figs. 17-12 to 17-16, see pages 432-433). The term foundation plants originated with the use of shrubs around the foundations of homes when foundations were exposed a foot or so above ground level. The term still persists to refer to plants used around the base of the home. Shrubs may be multistemmed or single stemmed. Some trees can be grown as multistemmed shrubs. Flowering shrubs will generally bloom when the plant is 1 to 3 years old. Table 17-2 (see page 434) lists ornamental shrubs for landscaping.

[FIGURE 17-8 OMITTED]

[FIGURE 17-9 OMITTED]

GROUNDCOVERS

Groundcovers are useful in areas where turfgrass is not practical, including sloped and shaded sites. Groundcovers are also useful in borders. Many groundcovers are low-growing shrubs. Some of them have a spreading habit to fill in an area, whereas others will spread slowly or not at all. Some groundcovers will grow as vines if they are provided with a vertical surface, although they may also require some support (Fig. 17-17, see page 436). Table 17-3 (see page 437) lists some groundcovers with ornamental qualities. For more information on vines, see chapter 16.

[FIGURE 17-10 OMITTED]

SELECTING THE TREE, SHRUB, OR GROUNDCOVER

Several factors must be considered when one is selecting a woody plant for landscape use. Ornamental qualities, seasonal interest, plant habit, and mature height and spread are aesthetic, design considerations. More practical considerations are disease and pest problems, soil and site requirements, cold and heat hardiness, and propensity for dropping fruit, limbs, or other plant parts that may be messy or become a nuisance.

Growing Requirements

The requirements for optimal conditions for plants include soil conditions, temperatures, and amount of sunlight available in a particular location. To understand the requirements of a particular plant, it is helpful to be aware of the plant's natural habitat. Table 17-4 (see page 438) lists plants for problematic soil conditions.

Right Plant for the Site

The amount of sunlight available on a particular site will determine whether a plant can thrive and grow there. Sunlight plays a crucial role in photosynthetic activity, flowering, and fruit development. Some plants can survive in a shady location but fail to flower or bear fruit. Plants that are not shade tolerant may be weak, small, or lanky. Conversely, shade-loving plants grown in full sun may suffer from leaf sunburn or simply die. Table 17-5 (see page 444) lists plants that tolerate shady growing conditions. Some trees are ornamental and do not grow too large. Such trees are ideal for small areas or patios or for growing under larger trees. A list of these is provided in Table 17-6 (see page 445). Other trees can grow quite large and provide ample shade for a yard or home. Some ornamental shade trees are listed in Table 17-7 (see page 447).

[FIGURE 17-11 OMITTED]

[FIGURE 17-12 OMITTED]

[FIGURE 17-13 OMITTED]

[FIGURE 17-14 OMITTED]

[FIGURE 17-15 OMITTED]

[FIGURE 17-16 OMITTED]

[FIGURE 17-17 OMITTED]

BUYING A TREE OR SHRUB: WHAT TO LOOK FOR

Healthy Plants

When purchasing a tree, check for defects in tree structure. Some major defects to avoid are double leaders, broken leaders, girdling, or any kind of damage on the trunk or main stem. Look for damaged branches and signs of disease. The latter may be difficult to detect if you are purchasing a tree during the dormant season. Avoid root-bound plants. Purchase plants from a reputable nursery whenever possible or be prepared for inferior quality. Many nurseries have a replacement policy, so check before purchasing.

Improved cultivars are often more expensive to purchase than unimproved plants of the same species. But the extra cost is usually worth it. If you are purchasing a tree that is prone to pests and diseases, such as crabapples, research the cultivars that are disease and pest resistant. Talk to your local nursery professionals for guidance in selecting superior plants. Sometimes local nurseries do not carry the cultivar you want. Then, if possible, locate a reputable mail-order source to obtain such plants. If you purchase plants from other regions, be sure they are going to be hardy in your area. It is preferable to buy plants that have been naturally selected for hardiness in your zone or a colder zone. You should never purchase a plant from a warmer zone. The source of seed plays an important role in seed-propagated species. As much as possible, buy plants that were grown from seed collected in your soil and climate types. Deer resistance can be an important factor in tree selection in some areas. Table 17-8 lists some commonly available woody plants that deer do not like to eat.

Avoid purchasing weedy trees. Some trees are very fast-growing, but the result is a weak tree. Willow trees, for example, grow very rapidly, averaging 3 to 4 feet of growth per year. However, their branches shed readily in winds and storms, and leaves, twigs, and branches drop throughout the season. Other trees are considered weedy when they release a multitude of seeds that exhibit a high degree of germination. Unwanted tree seedlings emerge in flower beds, lawns, and vegetable gardens. Table 17-9 (see page 450) lists some trees and shrubs that can become weedy or invasive in some areas. For some species, there are improved cultivars that display superior performance and may thus not be considered weedy. It is best to consult local extension personnel or nursery professionals for guidance.

Native Plants

Many woody plants used for ornamental purposes have originated in the region where they are grown. Others have been introduced from Europe, Asia, Australia, Africa, and South America. The introduced plants owe a large portion of their success in exotic environments to their adaptability. However, native plants are also adaptable and may be more likely to adapt to the soil characteristics of their place of origin. Understanding the native habitat of woody plants can be key to growing healthy plants in the landscape environment. Shade-loving plants should not be grown in full sun; upland plants do not tolerate wet feet. It is important to learn where a plant originated and what the soil and climate characteristics are, especially characteristics such as soil moisture and prevailing temperatures, before selecting a tree for a specific use. In this way, mistakes that result in the loss of trees in a few years can be avoided.

Special Considerations

If you are purchasing a tree for its ornamental fruit or flowers, be aware of fruit drop. Many trees drop their fruits and even seeds, over sidewalks, on cars, and at entryways to homes. The result is a continual mess as plant parts are tracked inside the home. If you must have such a plant, locate it farther away from the entryway and driveway, or parking area. Other trees, such as mulberries, produce fruits that birds love to eat. Use these with caution!

When selecting a shrub, the branch structure is often less important than it is for trees. Some factors to consider are weediness or invasiveness, pest and disease resistance, dwarf versus standard size (available in a limited number of species), and shade or sun preference. Most ornamental shrubs are valued for their showy flowers. Some of these, such as roses (Rosa spp.) and rose of Sharon (Hibiscus syriacus), are available in a variety of colors. Others are available only in white, such as smooth leaf hydrangea (Hydrangea arborescens) and common mockorange (Philadelphus coronarius) or yellow such as Japanese kerria (Kerria japonica), or other single colors. Some shrubs, such as Tatarian dogwood (Cornus alba), and wintercreeper (Euonymus fortunei) are available with variegated leaves (Fig. 17-18). Shrubs that are used for their "greenness" include evergreens such as yews and junipers and deciduous shrubs such as privet and boxwood (some boxwoods are evergreen) (Fig. 17-19).

BUYING A TREE OR SHRUB: HOW PLANTS ARE SOLD

Woody plants are available in several different ways: balled and burlapped, bare root, bag grown, container grown and field potted, or mechanically transplanted. The method of growing trees is directly related to the production methods used at the nursery where they are grown. Some trees cannot be grown as well in containers as in the field, while others will not obtain the desired size and height unless grown in the field. The different growing methods are discussed in more detail later.

Balled and Burlapped

Balled-and-burlapped trees have been grown for a period of several years in the ground in nurseries. They are dug up, keeping as much of the root mass intact as possible. This is generally accomplished by digging up a large area around the trunk of the tree, lifting it out of the ground, and placing it on burlap (Fig. 17-20). The burlap is tied around the root ball and the base of the trunk to move the tree with as little disturbance as possible. Trees are handled in this manner during dormancy when the ground is no longer frozen, as in late winter to early spring.

The advantages of using this method are that you have a large, established tree and do not have to wait years for it to begin providing shade or filling in an area. Balled-and-burlapped trees can be moved at any time of year, although summer-transplanted trees must be closely monitored to make sure the root ball does not dry out. The disadvantage is that balled-and-burlapped trees are very heavy. It can be costly to dig and move trees. And when they become quite large, special equipment is necessary. Some larger trees are moved with a tree spade and placed directly into a hole that has been prepared by the same equipment.

[FIGURE 17-18 OMITTED]

[FIGURE 17-19 OMITTED]

Bare Root

Bare-root trees and shrubs are dug up and have the soil rinsed from the roots. The roots are protected from drying by plastic, hydration gels or some other moisture-retaining substance. The disadvantage of this method is that a tree or shrub can only be handled in this manner during dormancy, so the window of opportunity is limited. The advantage of this method is that the bare-root plant is usually young and is light-weight, making shipping costs lower than those for other methods.

Bag Grown

Bag-grown trees are planted in field conditions, but in geotextile fabric bags rather than in the ground. The bags are placed into holes and filled with field soil and the trees are planted in them. The bag acts as a root-pruning system (Fig. 17-21). The advantage of this method is that the root system is not disturbed when planting, and the bag permits a well-developed root system to form. The disadvantage is the bags are more costly than growing directly in the ground.

Container Grown and Field Potted

Woody plants that are grown from a cutting or seed in containers need never have their root systems disturbed. They can be transplanted any time the ground is not frozen. Both evergreen and deciduous plants can be handled this way. Smaller trees that are field-grown and dug up with their root ball may be placed into pots rather than balled and burlapped.

Mechanically Transplanted

Some trees are simply moved from one location (in a nursery or from a site) to another. This can all be done in a single procedure. First, a tree spade is used to dig a hole at the intended site, then the tree space is driven back to the tree site, the soil is left there, and the tree is dug carried back to the intended site, and placed precisely into the hole. Trees that need to be removed for construction purposes are sometimes saved using this method. The advantage is that the tree can be saved and placed in a more suitable location. The disadvantage is that trees often do not survive transplanting due to the loss of large amounts of roots.

[FIGURE 17-20 OMITTED]

[FIGURE 17-21 OMITTED]

HOW TO PLANT

Balled and Burlapped

When you receive the balled and burlapped tree, you should handle the plant as little as possible, being careful not to disturb the roots. Do not carry the plant by the trunk, as this will loosen it from the root ball. Support the base of the root ball when moving or carrying it. Have the hole prepared ahead of time. The hole should have a diameter about 12 inches wider than the root ball and the same depth as the root ball. Leave the burlap on the root ball but cut the string that is around the trunk and around the top of the root ball. Cut any wire that is wrapped around the ball. Place the ball along with the cloth into the hole you have prepared. Be sure no wires or strings restrict the root ball. If the burlap is not adequately loosened and the string is cut away, the tree is in danger of having its root system girdled. This results in a poorly growing tree that may eventually die because the root system cannot develop as needed to sustain the growth of the tree.

After you have gently placed the tree in the hole, backfill with some of the soil from the hole and firm it as you go to remove any air pockets. Be sure to plant the tree at the same depth as it was before. You should be able to detect the soil line on the trunk. Continue backfilling with soil to fill in the gaps around the sides of the root ball area and keep the trunk at the proper level.

You may tamp lightly on the soil around the tree to eliminate any air pockets that may have developed during the transplanting process. Do not stomp as this may compact the soil and will surely damage the fine roots and root hairs that are so vital to the tree's successful move. Make a dike around the plant about the diameter of the root ball or slightly larger, about 2 inches high, with some of the loose soil and water the plant in (Fig. 17-22).

Remove any string that may have been tied to hold the branches out of the way. Remove broken branches, second leaders, or other problematic growth at this time; otherwise, it is not necessary to prune. Stake the tree if necessary if conditions are windy. Fertilize lightly and keep the tree adequately watered. The first year is most crucial in establishing a well-developed root system. Once the root system has developed, the tree should be able to obtain the water it needs from the soil.

Bare Root

Bare-root trees can only be safely shipped and transplanted during their dormant season. They should be packaged in a medium that prevents the roots from drying out altogether, because even though they are dormant, they are still living organisms with some basic needs. Sawdust, mulch, potting soil, and so on can be used. The roots should be kept moist. Although plants should not be frozen, cool temperatures are preferable to warm ones as the respiration rate of the tree will be lower. Likewise, keep these trees out of full sun. Before planting, bare-root trees should be soaked in room-temperature water for 2 to 6 hours (Fig. 17-23). Check for girdling or badly kinked roots and remove them to avoid a continuation of the problem after planting, Remove damaged roots as well.

[FIGURE 17-22 OMITTED]

[FIGURE 17-23 OMITTED]

The planting hole should accommodate the root depth. In the center of the hole, build a cone with soil to drape the roots over, spreading them out as evenly as possible out in all directions. Visually locate the soil line on the trunk and plant at the same level in the new hole. Once the tree has been properly placed, begin backfilling with native soil. Carefully backfill between roots, spreading them out vertically. Place the uppermost root slightly angled down from the soil surface. The roots should not be bent to accommodate too small of a hole, but rather, the hole should be dug wide enough to accommodate the roots. Do not cut the roots, but rather dig a long trench if necessary to accommodate long roots. Stake the tree. Fertilize and irrigate as for other types of trees.

Container Grown

Perhaps the first instruction for planting container-grown trees is to avoid those that are pot bound. Their roots are already growing in a circling fashion, and this inevitably leads to girdling of the trunk after planting in the ground. Also, root-bound container-grown trees often have too many roots on the outer edge of the root ball, rather than evenly distributed throughout the root ball. If you must use such a tree, then make three to four vertical slices from the top to the bottom of the root ball before planting. The slices should be about 1 inch deep.

If upon inspection of a tree after removing it from the container, the root system is well developed and not pot bound, slicing through the root system is not necessary. Water the plant well several hours to a day before removing it from the container so that the root ball holds together for handling during planting. Dig a hole of the same size as the container. It should be the exact depth of the root ball, but wider, to accommodate spreading the roots out and to provide loose, friable soil in the surrounding area where new root growth is desired. Using both hands on the bottom of the root ball, pull the roots out from the bottom to direct them to grow downward into the space provided. Be sure to place the root ball into the hole so that the soil line on the trunk is level with the top of the hole.

MAINTENANCE

Trees and shrubs require varying amounts of maintenance, mainly depending on species. Pruning is required at different levels for shrubs, fruit trees, nut trees, and trees grown for ornamental purposes. It would be wise to familiarize yourself with pruning requirements of a plant before purchasing it. Low-maintenance plants are available, although extra effort may be required to identify and locate them. However, this effort will be worth it in the long run if you prefer not to spend much time working in your yard or garden.

Pruning

Pruning is a very important maintenance procedure for woody plants. It is also the one that many people know the least about. Pruning is covered in detail in chapter 11, but here are some tips and guidelines:

1. Understand the basics of pruning: why it is done, when it is done, and what the effect will be.

2. Know your plant: how it responds to pruning and any particular hazards or weaknesses in that species (some respond to pruning better than others).

3. Use good-quality tools.

4. Do not top trees! It often leads to their ultimate demise because they cannot recover from the assault on their natural defense system.

Removing

Tree removal is usually performed when the tree has become hazardous. Many causes can lead to a hazardous condition. Sometimes the root system has been damaged by compaction or roots have been severed during a construction project or a tree may be declining naturally. Sometimes a tree requires removal because it is in the way of a proposed construction project. Tree removal of larger, older trees, requires the help of a professional. Special equipment such as truck-mounted hydraulic lifts are necessary. Some of the dangers include the presence of electrical power lines, houses, and other structures in the way of branches that must be dropped. Only someone properly trained in safe procedures for tree removal should perform this task.

Stump Removal

Stumps can be left to decompose over a period of years. They may also be ground with a stump grinder, which removes the trunk, but leaves the root system, including large lateral roots near the soil surface. Eventually the roots should decompose. However, some tree roots generate shoots along their surface, even after the main trunk has been removed. It may be necessary to apply herbicide to prevent suckering if this is a problem. Herbicide can be painted directly on the stump to prevent suckering as well. The active ingredient in stump herbicides is triclopyr.

Mulching

Trees may be mulched after planting to help with weed suppression, moisture retention, prevention of soil compaction, and reduced competition with turf. Mulching under a tree eliminates damage done to trunks by lawn mowers and string trimmers.

Mulch should be applied at least out to the dripline of trees. This is the circular line formed by the outermost tips of branches. Each year, as a tree grows, the mulched area should increase. However, mulch should not be in contact with the trunk. Pull mulch at least 6 inches away from the trunk to prevent bark decay. Mulch can be applied at a depth of 2 to 4 inches. If it is deeper than that, it smothers the surface roots. The mulch will slowly decompose over time and will require replacement about once a year.

If wood products are used, be sure you know the source and do not use mulch from diseased trees. If very fresh mulch is used, some feel that microorganisms in the mulch will use soil nitrogen. These microorganisms help to break down organic matter but require nitrogen for their reproduction. This situation can be avoided by adding a low level of nitrogen fertilizer to the mulched area.

Relocating

It is best to relocate a tree when it is still quite small. When a tree is moved, it is necessary to retain as much of the root system as possible. Although most of the root mass can be dug up within 1 to 3 feet of the tree trunk (depending on tree size), many of the long roots will be severed in the moving process. Yet, the root ball for even a young tree can be quite heavy. A tree spade is used to move larger trees as described earlier in the section on mechanically transplanted. The tree should be cared for as with a newly planted tree, especially with respect to irrigation to ensure new root development as soon as possible. Trees are usually moved in this manner in spring or fall, when mild temperatures prevail.

How to Dig up a Shrub

If you know ahead of time that you want to relocate a shrub in your yard, then you can make preparations during the prior autumn that will reduce shock to the shrub. Prune the roots of the shrub by cutting into the soil with a shovel in a circle around the shrub. You should cut at about the same diameter as the root ball will be when you move the shrub the following spring. This root pruning technique stimulates new root growth within the cut area. In the following spring, dig the hole where the shrub will go. Water the shrub well a day or so before digging it up to ensure that the root ball will hold together. Dig up the shrub, retaining as much of the root ball as possible. Use a tarp to set the root on for transporting it to the new location. Make sure the hole you have dug is large enough to accommodate the entire root ball and then gently place the shrub into the hole. Backfill as necessary to fill in all the spaces and water and fertilize.

SUMMARY

Trees and shrubs provide a backbone for the plantings in a home. Woody groundcovers can provide a solution for problematic areas, such as heavy shade or difficult-to-mow areas. Although all of these plants add beauty to any landscape, they also serve other functions, such as providing windbreaks, shade for the home, and habitats for wildlife. Problems can arise, however, when a tree or shrub is planted in the wrong place. This happens, for example, when trees that will mature to a large size are planted too close to power lines or buildings. Common problems with trees in urban settings are restricted root areas and damage to tree roots due to construction. Rototilling under trees to plant flowers or other plants also damages many of the important feeder roots that grow near the soil surface.

Trees, shrubs, and groundcovers should be selected for the site where they will be planted. Practices to grow and maintain a healthy tree begin with selection of a healthy plant, followed by proper training and pruning, proper cultural practices, and minimizing stress to the plant.

Trees and shrubs are available as bare-root, balled-and-burlapped, or container-grown plants. Vines and groundcovers are generally available as container-grown plants. All of these may be purchased and planted at various times of year, although the dormant season is the best time to plant a deciduous tree or shrub. Balled-and-burlapped and container-grown trees may be planted any time of year, but special care must be taken during times of high heat and low rainfall. By selecting the right plant for the site, giving consideration to root structure, maintenance needs, and selection of a healthy plant, a woody plant may become part of the landscape for a very long time. It will thus fulfill its aesthetic or utilitarian function throughout its lifetime.

HANDS-ON ACTIVITIES

* Develop a top 20 list of trees and one for shrubs that are particularly suited for your area. Include features such as size and shape, sun and shade requirements, soil requirements, and diseases or other common problems. Identify one or more aesthetic qualities about each plant.

* Research and identify native trees and shrubs that grow in challenging sites in your geographical area: wet, dry, slopes, poor soils, and shade.

* Take a plant identification walk with an instructor or woody plant professional in your area. Learn to identify plants from a distance, and take note of the conditions in which they thrive or struggle. Learn to recognize common problems of woody landscape plants: poor placement, disease susceptibility, mismanagement, and others.

REVIEW QUESTIONS

1. Name three ways that trees provide practical solutions.

2. What is the definition of a specimen tree?

3. The people whose job it is to monitor the health of trees and care for them are called--.

4. Describe the effect on trees of rototilling under them.

5. Landscape plants that are used around the base of a home are called--.

6. Name three places or situations in which groundcovers are particularly useful.

7. What is the main problem with fast-growing trees?

8. What are the advantages and disadvantages of balled-and-burlapped trees?

9. What are the advantages and disadvantages of container-grown and bag-grown trees?

10. What are the advantages and disadvantages of bare-root trees?

SELECTED REFERENCES

Bridwell, F. M. (1994). Landscape plants: their identification, culture, and use. Clifton Park, NY: Thomson Delmar Learning.

Dirr, M. A. (1975). Manual of woody landscape plants. Champaign, IL: Stipes.

Gilman, E. F. (1997). Trees for urban and suburban landscapes. Albany, NY: Thomson Delmar Learning.

Shigo, A. L. (1995). 100 tree myths. Denham, NH: Shigo and Trees, Associates.

Dr. Marietta Loehrlein currently teaches horticulture classes at Western Illinois University in Macomb, Illinois. She earned both her bachelor's degree in Agronomy and her master's degree in Plant Genetics at The University of Arizona. Her master's research project was concerned with germination problems associated with triploid seeds, from which seedless watermelons grow. Following that she worked for 5 years in a breeding and research program for Sunworld, International near Bakersfield, California. She worked with peaches, nectarines, plums, apricots, and cherries. Then she returned to school to earn her Ph.D. in Horticultural Genetics at The Pennsylvania State University. Her Ph.D. research focused on flowering processes in regal pelargonium (also called Martha Washington geraniums). While at The Pennsylvania State University, she bred a new cultivar of regal pelargonium, "Camelot." At Western Illinois University, Dr. Loehrlein teaches nine courses: Greenhouse and Nursery Management, Introductory Horticulture, Landscape Design, Landscape Management, Home Horticulture, Plant Propagation, Turf Management, and two courses in Plant Identification.
TABLE 17-1
Deep- and Shallow-Rooted Trees

COMMON                 SPECIES                    DEPTH

Bald cypress           Taxodium distichum         Deep

Beech                  Fagus spp.                 Shallow

Birch                  Betula spp.                Shallow

Black tupelo           Nyssa sylvatica            Deep

Cottonwood             Populus deltoides          Shallow

Crape myrtle           Lagerstroemia indicans     Shallow

Hackberry              Celtis occidentalis        Shallow

Hickory                Carya spp.                 Deep

Hornbeam               Carpinus spp.              Deep

Kentucky yellowwood    Cladastris kentuckea       Deep

Loblolly pine          Pinus taeda                Deep

Norway maple           Acer platanoides           Shallow

Oak                    Quercus spp.               Deep

Olive                  Olea spp.                  Deep

Silver maple           Acer saccharinum           Shallow

Spruce                 Picea spp.                 Shallow

Sugar maple            Acer saccharum             Shallow

TABLE 17-2
Ornamental Shrubs for the Landscape

COMMON NAME                  SPECIES                       ZONES

Alpine currant               Ribes alpinum                 2-7

American cranberrybush       Viburnum trilobum             2-7
  viburnum

Amur privet                  Ligustrum amurense            4-7

Arrowwood viburnum           Viburnum dentatum             3-8

Azalea                       Rhododendron spp.             5-9

Bearberry cotoneaster        Cotoneaster dammeri           5-7

Black chokeberry             Aronia melanocarpa            3-8

Bumald spiraea               Spiraea x bumalda             3-8

Burkwood viburnum            Viburnum x burkwoodii         5-8

Bush cinquefoil              Potentilla fruticosa          2-6

Buttonbush                   Cephalanthus occidentalis     5-11

Carolina allspice            Calycanthus floridus          4-9

Chenault coralberry          Symphoricarpos x              4-7
                               chenaultii

Chengtu lilac                Syringa swenginzowii          5-6

Common box                   Buxus sempervirens            5-8

Common flowering             Chaenomeles speciose          4-8
  quince

Common lilac                 Syringa vulgaris              3-7

Common mock orange           Philadelphus coronarius       4-8

Common ninebark              Physocarpus opulifolius       2-7

Common snowberry             Symphoricarpos albus          3-7

Common winterberry           Ilex verticillata             3-9

Doublefile viburnum          Viburnum plicatum var.        5-7
                               tomentosum

Dwarf fothergilla            Fothergilla gardenii          5-8

Dwarf Korean lilac           Syringa meyeri                3-7

European cranberrybush       Viburnum opulus               3-8
  viburnum

Flowering almond             Prunus triloba                3-6

Forsythia                    Forsythia x intermedia        5-9

Fragrant sumac               Rhus aromatica                3-9

Goldflame honeysuckle        Lonicera x heckrottii         5-9

Indiancurrant coralberry     Symphoricarpos orbiculatus    2-7

Japanese barberry            Bereberis thunbergii          4-8

Japanese flowering quince    Chaenomeles japonica          5-8

Japanese privet              Ligustrum japonicum           7-10

Japanese tree lilac          Syringa reticulata            3-7

Judd viburnum                Viburnum x juddii             4-8

Kerria, black jetbead        Rhodotypos scandens           4-8

Koreanspice viburnum         Viburnum carlesii             5-8

Littleleaf box               Buxus microphylla             6-9

Littleleaf lilac             Syringa microphylla           4-7

Mentor barberry              Bereberis x mentorensis       5-8

Meserve holly                Ilex x meservae               4-7

Oakleaf hydrangea            Hydrangea quercifolia         5-9

Oregon grapeholly            Mahonia aquifolium            5-8

Panicle hydrangea            Hydrangea paniculata          3-8

Purple beautyberry           Callicarpa dichotoma          5-8

Red chokeberry               Aronia arbutifolia            4-9

Rhododendron                 Rhododendron spp.             4-8

Rockspray                    Cotoneaster horizontalis      5-7

Rugose rose                  Rosa rugosa                   2-7

Sapphireberry                Symplocos paniculata          4-8

Scarlet firethorn            Pyracantha coccinea           5-9

Shrub rose                   Rosa spp.                     4-5

Smooth hydrangea             Hydrangea arborescens         4-9

Spreading cotoneaster        Cotoneaster divaricatus       4-7

Summersweet                  Clethra alnifolia             4-9

Tatarian dogwood             Cornus alba                   3-7

Trumpet honeysuckle,         Lonicera sempervirens         4-9
  coral honeysuckle

Vanhoutte spiraea            Spiraea x vanhouttei          3-8

Wayfaringtree viburnum       Viburnum lantana              4-7

Weigela                      Weigela florida               5-8

Winged euonymus              Euonymus alatus               4-8

Winter honeysuckle           Lonicera fragrantissima       4-8

Wintercreeper euonymus       Euonymus fortunei             5-8

TABLE 17-3
Ornamental Qualities of Groundcovers

COMMON           SPECIES            ORNAMENTAL QUALITY          ZONES

Bearberry        Arctostaphylos     Glossy-leaved, matted       3-7
                   uvaursi            groundcover

Bunchberry       Cornus             Deciduous matted            2-5
                   canadensis         groundcover, lustrous
                                      dark green leaves,
                                      small red fruit in
                                      fall

Canby            Paxistima          Evergreen groundcover       4-7
  paxistima        canbyi

Cotoneaster      Cotoneaster        Several species of low-     4-7
  species          spp.               growing shrubby
                                      groundcovers with
                                      arching, spreading
                                      branches

Creeping         Juniperus          Dense, mat-like ever-       3-9
  juniper          horizontalis       green shrub; very
                                      low-growing

Creeping         Liriope spicata    Grass-like clumps with      5-9
  lilyturf                            purple spikes of
                                      flowers in spring

Creeping         Gaultheria         Evergreen, low              5-8
  winter-          procumbens         spreading groundcover;
  green                               glossy, minty-scented
                                      leaves; fruit is
                                      large, red capsule

Dwarf            Stephandra         Dissected, crinkly          4-8
  cutleaf          incisa             foliage; tough, 3
  stephandra       'Crispa'           feet tall spreading,
                                      slightly mounded
                                      groundcover,
                                      foundation shrub;
                                      drapes over walls.

Honeysuckle      Lonicera spp.      Fast-growing vine with      3-9
  species                             tubular flowers of
                                      cream, yellow, red,
                                      or orange

Indiancurrant    Symphoricarpos     Spreading, arching shrub,   3-6
  coralberry       orbiculatus        red fruits in fall

Labrador tea     Ledum              Evergreen, dwarf, white     2-6
                   groenlandicum      flowers in spring

Savin juniper    Juniperus          Evergreen, wide-spreading   3-7
                   sabina             vase-shaped blue-green
                                      shrub

Sweetgale        Myrica gale        Glossy blue-green           1-6
                                      fragrant foliage, low
                                      shrub

Trailing         Epigaea repens     Evergreen, low-growing      3-8
  arbutus                             shrub

Vinca            Vinca minor        Shade-loving groundcover    4-8
                                      with small purple
                                      flowers in spring

Wintercreeper    Euonymus           Creeping groundcover or     5-8
                   fortunei           bushy plant with
                                      slender stems that
                                      require support to
                                      climb; leaf
                                      variegations numerous

Yellowroot       Xanthorhiza        Matted groundcover,         3-9
                   simplicissima      yellow bark, bright
                                      green in summer,
                                      yellow in fall

TABLE 17-4
Trees, Shrubs, Vines, and Groundcovers for Problematic Soil
Conditions

COMMON                                   SPECIES               ZONE

                                           Dry

                                          Trees

American beech                 Fagus grandiflora               4-9

Chinese juniper                Juniperus chinensis             3-8

Colorado spruce                Picea pungens                   3-7

European mountainash           Sorbus aucuparia                3-7

European white birch           Betula pendula                  3-5

Hedge maple                    Acer campestre                  5-8

Japanese maple                 Acer palmatum                   5-9

Norway maple                   Acer platanoides                4-7

Pin oak                        Quercus palustris               4-9

Quaking aspen                  Populus tremuloides             2-6

Swiss mountain pine            Pinus mugo                      3-7

Swiss stone pine               Pinus cembra                    3-6

                                          Shrubs

Alpine currant                 Ribes alpinum                   3-7

Burning bush                   Euonymus alatus                 4-8

Bush cinquefoil                Potentilla cinquefolia          2-7

Common flowering quince        Chaenomeles speciose            4-9

Dwarf Eastern white pine       Pinus strobus 'Nana'            3-7

Eastern ninebark               Physocarpus opulifolius         3-6

Japanese kerria                Kerria japonica                 5-9

Mentor barberry                Berberis x mentorensis          5-9

Mountain pieris                Pieris floribunda               5-7

Redvein enkianthus             Enkianthus campanulatus         5-8

Rockspray cotoneaster          Cotoneaster hortizontalis       5-8

Rosemary                       Rosmarinus officinalis          7-10

Spreading cotoneaster          Cotoneaster divaricatus         5-8

Thunberg spiraea               Spiraea thunbergii              4-9

Vanhoutte spiraea              Spiraea   vanhouttei            3-8

Yucca species                  Yucca spp.                      4-9

                                  Vines and Groundcovers

Bearberry                      Arctostaphylos uva-ursi         3-7

Creeping juniper               Juniperus horizontalis          3-9

Honeysuckle species            Lonicera spp.                   3-9

Indiancurrant coralberry       Symphoricarpos orbiculatus      3-6

Scarlet clematis               Clematis texensis               4-8

                                           Wet

                                          Trees

Catalpa                        Catalpa spp.                    4-9

Dawn redwood                   Metasequoia                     5-9
                                 glyptostroboides

Eastern arborvitae             Thuja occidentalis              3-7

Green ash                      Fraxinus pennsylvanica          3-9

Pawpaw                         Asimina triloba                 5-8

Pecan                          Carya illinoinensis             5-9

Quaking aspen                  Populus tremuloides             2-6

Red maple cultivars            Acer rubrum                     3-9

River birch                    Betula nigra                    4-9

Sweetbay magnolia              Magnolia virginiana             5-9

Sweetgum                       Liquidambar styraciflua         5-9

White willow                   Salix alba                      3-9

                                          Shrubs

Arrowwood viburnum             Viburnum dentatum               4-9

Blackhaw viburnum              Viburnum prunifolium            3-9

Chokeberry species             Aronia spp.                     3-9

Eastern ninebark               Physocarpus opulifolius         3-6

European pussywillow           Salix caprea                    3-9

Fothergilla species            Fothergilla spp.                5-9

Gray dogwood                   Cornus racemosa                 3-7

Japanese kerria                Kerria japonica                 5-9

Oakleaf hydrangea              Hydrangea quercifolia           5-9

Redosier dogwood               Cornus stolonifera (Cornus      3-8
                                 sericea)

Smooth hydrangea               Hydrangea arborescens           4-9

Tartarian dogwood              Cornus alba                     3-8

Virginia sweetspire            Itea virginica                  6-9

White fringetree               Chionanthus virginicus          5-9

Winterberry                    Ilex verticillata               4-9

                                  Vines and Groundcovers

Climbing hydrangea             Hydrangea petiolaris            5-7

Creeping lilyturf              Liriope spicata                 5-9

Dwarf cutleaf stephandra       Stephandra incisa 'Crispa'      5-8

Gray willow                    Salix repens                    4-9

Indiancurrant coralberry       Symphoricarpos orbiculatus      2-7

Labrador tea                   Ledum groenlandicum             2-6

                                           Acid

                                          Trees

American holly                 Ilex opaca                      6-9

Blue ash                       Fraxinus quadrangulata          4-8

Eastern white pine             Pinus strobus                   3-9

Flowering dogwood              Cornus florida                  5-8

Franklin tree or Ben           Franklinia alatamaha            6-7
Franklin tree

Freeman hybrid maple           Acer x freemanii                3-9

Green ash                      Fraxinus pennsylvanica          3-9

                                          Trees

Hedge maple                    Acer campestre                  5-8

Japanese maple                 Acer palmatum                   5-9

Kousa dogwood                  Cornus kousa                    5-7

Norway spruce                  Picea abies                     3-8

Pin oak                        Quercus palustris               4-9

Scarlet oak                    Quercus coccinea                5-9

Sour gum                       Nyssa sylvatica                 5-9

Sourwood                       Oxydendrum arboreum             5-9

Swiss stone pine               Pinus cembra                    3-6

White oak                      Quercus alba                    4-9

Willow oak                     Quercus phellos                 6-9

                                          Shrubs

Carolina rhododendron          Rhododendron                    5-7
                                 carolinianum

Catawba rhododendron           Rhododendron catawbiense        4-7

Corneliancherry dogwood        Cornus mas                      5-8

Dwarf and large fothergilla    Fothergilla gardenii,           5-9
                                 Fothergilla major

Flame azalea                   Rhododendron                    5-8
                                 calendulaceum

Highbush blueberry             Vaccinium corymbosum            4-9

Japanese pieris, Japanese      Pieris japonica                 6-8
  andromeda

Korean rhododendron            Rhododendron                    5-7
                                 mucronulatum

Meserve holly                  Ilex x meservae                 5-8

Mountain laurel                Kalmia latifolia                5-9

Mountain pieris                Pieris floribunda               5-7

Pagoda dogwood                 Cornus alternifolia             4-7

Pearlbush                      Exochorda racemosa              5-9

Red and black chokeberry       Aronia arbutifolia, Aronia      3-9
                                 melanocarpa

Redvein enkianthus             Enkianthus campanulatus         4-7

Sheep laurel                   Kalmia angustifolia             2-7

Summersweet clethra            Clethra alnifolia               3-7

Viburnum species               Viburnum spp.                   3-8

                                  Vines and Groundcovers

Bunchberry                     Cornus canadensis               2-5

Highbush blueberry             Vaccinium corymbosum            5-8

Lowbush blueberry              Vaccinium angustifolium         2-5

Sargent's weeping              Tsuga canadensis 'Pendula'      4-8
  hemlock

Trailing arbutus               Epigaea repens                  3-8

                                         Alkaline

                                          Trees

Allegheny serviceberry         Amelanchier laevis              4-8

American mountainash           Sorbus americana                2-6

Black walnut                   Juglans nigra                   4-9

Blue ash                       Fraxinus quadrangulata          4-7

Northern catalpa               Catalpa speciosa                4-8

Chinese juniper                Juniperus chinensis             4-9

Crabapples                     Malus spp.                      5-9

Cucumbertree magnolia          Magnolia acuminata              4-8

Dogwood species                Cornus spp.                     3-7

Downy serviceberry             Amelanchier arborea             4-9

Eastern arborvitae             Thuja occidentalis              3-7

Eastern redbud                 Cercis canadensis               4-9

European alder                 Alnus glutinosa                 4-7

Goldenraintree                 Koelreuteria paniculata         5-9

                                          Trees

Common hackberry               Celtis occidentalis             3-9

Hawthorn species               Crataegus spp.                  4-7

Kentucky coffeetree            Gymnocladus dioica              4-7

Ohio buckeye                   Aesculus glabra                 4-7

Pecan                          Carya illinoinensis             5-9

Quaking aspen                  Populus tremuloides             2-6

Saucer magnolia                Magnolia soulangiana            5-9

Shagbark hickory               Carya ovata                     4-8

Shingle oak                    Quercus imbricaria              5-9

Spruce                         Picea spp.                      4-8

Sweetgum                       Liquidambar styraciflua         5-9

White fir                      Abies concolor                  4-7

White oak                      Quercus alba                    4-9

                                          Shrubs

Bottlebrush buckeye            Aesculus parviflora             5-9

Butterflybush                  Buddleia davidii                4-8

Crape myrtle                   Lagerstroemia indicans          7-9

Flowering quince               Chaenomeles speciosa            4-9

Hydrangea species              Hydrangea spp.                  4-9

Jetbead                        Rhodotypos scandens             5-8

Lilac species                  Syringa spp.                    3-8

Serviceberry                   Amelanchier canadensis          4-8

Showy forsythia                Forsythia   intermedia          5-8

Smokebush                      Cotinus coggygria               5-7

Weigela                        Weigela florida                 5-9

Yucca                          Yucca spp.                      4-9

                                  Vines and Groundcovers

Australian saltbush            Atriplex semibaccata            4-5

TABLE 17-5
Trees, Shrubs, Vines, and Groundcovers for Shade

COMMON                   SPECIES                         ZONE

                                    Trees

Canadian hemlock         Tsuga canadensis                3-7

Flowering dogwood        Cornus florida                  5-9

Japanese maple           Acer palmatum                   5-8

Pagoda dogwood           Cornus alternifolia             3-7

Redbud                   Cercis canadensis               4-9

Witchhazel               Hamamelis spp.                  4-8

                                    Shrubs

Gray dogwood             Cornus racemosa                 3-8

Hydrangea species        Hydrangea spp.                  4-9

Japanese kerria          Kerria japonica                 4-9

Nannyberry viburnum      Viburnum lentago                3-7

Oregon grapeholly        Mahonia aquifollium             5-8

Rhododendron species     Rhododendron spp.               5-9

Yew                      Taxus baccata                   6-7

                            Vines and Groundcovers

English ivy              Hedera helix                    4-9

Vinca                    Vinca minor                     4-8

Virginia creeper         Parthenocissus quinquefolia     4-9

Wintercreeper            Euonymus fortunei               5-9

TABLE 17-6
Small Ornamental Trees (Under 25 Feet)

COMMON NAME                  SPECIES                         ZONES

Apple serviceberry           Amelanchier x grandiflora       4-9

Autumn-olive                 Elaeagnus umbellata             4-8

Blireiana plum               Prunus x blireiana              5-9

Corneliancherry              Cornus mas                      4-7
  dogwood

Crabapples                   Malus hybrida                   4-8

Crape myrtle                 Lagerstroemia indicans          7-10

Desert willow                Chilopsis linearis              7-10

Eastern redbud               Cercis canadensis               4-9

Feathery buckthorn           Rhamnus frangula                3-7

Florida maple, Southern      Acer barbatum                   7-9
  sugar maple

Flowering dogwood            Cornus florida                  5-9

Franklin tree, Ben           Franklinia alatamaha            6-9
  Franklin tree

Fullmoon maple               Acer japonicum                  5-7

Goldenchain tree             Laburnum x watereri             5-7

Green hawthorn               Crataegus viridis               4-7

Japanese apricot             Prunus mume                     6-9

Japanese maple               Acer palmatum                   5-8

Korean stewartia             Stewartia koreana               5-8

Kousa dogwood                Cornus kousa                    5-8

Kwanzan cherry               Prunus serrulata 'Kwanzan'      6-9

Lily magnolia                Magnolia liliiflora             5-8

Mimosa tree, silk tree       Albizia julibrissin             6-9

Pagoda dogwood               Cornus alternifolia             3-7

Purpleleaf plum              Prunus cerasifera               4-9

Sand cherry                  Prunus x cistena                3-7

Saucer magnolia              Magnolia soulangiana            5-9

Shogetsu cherry              Prunus serrulata 'Shogetsu'     5-9

Smoketree                    Cotinus coggygria               5-8

Star magnolia                Magnolia stellata               5-9

Threadleaf falsecypress,     Chamaecyparis pisifera          4-8
  Japanese falsecypress

Trident maple                Acer buergeranum                5-9

Weeping blue atlas cedar     Cedrus atlantica                6-9

Weeping cherry, weeping      Prunus subhirtella 'Pendula'    5-8
  Higan cherry

Weeping Katsura tree         Cercidiphyllum japonicum        5-8
                               'Pendula'

Witchhazel                   Hamamelis virginiana            3-8

TABLE 17-7

Ornamental Shade Trees

COMMON                  SPECIES                 ZONE

American linden         Tilia americana         2-8

American sweetgum       Liquidambar             5-9
                          styraciflua

Amur corktree           Phellodendron           4-7
                          amurense

Common hackberry        Celtis occidentalis     2-9

Cucumber magnolia       Magnolia acuminata      4-8

Freeman maple           Acer x freemanii        3-8

Ginkgo (male trees)     Ginkgo biloba           4-8

Goldenraintree          Koelreuteria            5-9
                          paniculata

Honeylocust-            Gleditsia               3-9
  thornless               triacanthos

Japanese zelkova        Zelkova serrata         6-9

Littleleaf linden       Tilia cordata           3-7

Northern red oak        Quercus rubra           3-9

Norway maple            Acer platanoides        3-8

Red maple               Acer rubrum             3-9

Sour gum, black gum     Nyssa sylvatica         5-9

Sugar maple             Acer saccharum          3-8

Tuliptree               Liriodendron            5-9
                          tulipifera

White ash               Fraxinus americana      3-9

White oak               Quercus alba            4-9

TABLE 17-8

Woody Plants Deer Do Not Like

COMMON                  SPECIES                 ZONES

                        Trees

Ash                     Fraxinus spp.           3-9

Cedar                   Cedrus spp.             6-9

Coast redwood           Sequoia sempervirens    7-9

Cypress                 Cupressus spp.          7-9

Douglas fir             Pseudotsuga             4-6
                          menziesii

False cypress           Chamaecyparis spp.      4-8

Fig                     Ficus carica            7-9

Fir                     Abies spp.              Varies

Hackberry               Celtis occidentalis     3-9

Hawthorn                Crataegus spp.          4-7

Japanese maple          Acer palmatum           5-8

Magnolia                Magnolia spp.           5-9

Maidenhair tree,        Ginkgo biloba           4-8
  ginkgo

Oak                     Quercus spp.            3-10

Pine                    Pinus spp.              2-7

Silk tree               Albizia julibrissin     6-9

Spruce                  Picea spp.              2-7

                        Shrubs

Barberry                Berberis spp.           3-8

Bottlebrush             Callistemon spp.        8-11

Boxwood                 Buxus spp.              6-9

Butterflybush           Buddleia davidii        5-9

California buckeye      Aesculus californica    7-8

Cotoneaster             Cotoneaster spp.        4-7

Currant                 Ribes spp.              2-7

Elaeagnus               Elaeagnus spp.          2-8

Firethorn               Pyracantha coccinea     6-9

                        Shrubs

Flowering quince        Chaenomeles spp.        4-8

Glossy abelia           Abelia x                6-9
                          grandiflora

Heath                   Erica spp.              5-7

Heavenly bamboo         Nandina domestica       6-9

Holly                   Ilex spp.               3-9

Japanese kerria         Kerria japonica         4-9

Juniper                 Juniperus spp.          2-9

Lilac                   Syringa spp.            3-7

Myrtle                  Myrtus communis         9-10

Oleander                Nerium oleander         8-11

Oregon grape holly      Mahonia aquifolium      5-7

Scotch heather          Calluna vulgaris        4-6

St. Johns wort          Hypericum spp.          4-8

Sumac                   Rhus spp.               3-9

Sweet box               Sarcococca              6-8
                          hookeriana

Viburnum                Viburnum spp.           3-7

TABLE 17-9

Weedy Trees and Shrubs

NAME                  BOTANICAL NAME          ZONES

Amur honeysuckle      Lonicera maackii        3-8

Amur maple            Acer ginnala            3-8

Amur privet           Ligustrum amurense      4-7

Autumn-olive          Elaeagnus umbellata     2-7

Boxelder              Acer negundo            3-9

Chinese elm           Ulmus parvifolia        5-9

Common chokecherry    Prunus virginiana       2-6

Eastern cottonwood    Populus deltoides       4-9

Eucalyptus            Eucalyptus spp.         7-10
  (some species)

European alder        Alnus glutinosa         4-7

Multiflora rose       Rosa multiflora         5-8

Russian mulberry      Morus alba var.         5-8
                        tatarica

Russian-olive         Elaeagnus               2-7
                        angustifolia

Siberian elm          Ulmus pumila            4-9

Silver maple          Acer saccharinum        3-9

Weeping willow        Salix alba 'Tristis'    2-8
COPYRIGHT 2008 Delmar Learning
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2008 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Author:Loehrlein, Marietta M.
Publication:Home Horticulture: Principles and Practices
Date:Jan 1, 2008
Words:8080
Previous Article:Chapter 16: flower gardening.
Next Article:Chapter 18: landscape design, installation, and maintenance.
Topics:

Terms of use | Privacy policy | Copyright © 2019 Farlex, Inc. | Feedback | For webmasters