Reducing Winter Injury

Some types of winter damage can be eliminated by winterizing the landscape during the preceding autumn. Other types can be reduced by better design of the grounds. Still other winter injuries can only be minimized, never totally eliminated.

Windburn Windburn can be eliminated in the design stage of land­scaping by selecting deciduous species, rather than evergreens, for windy corners and other exposed locations. If evergreens are important to the design or already exist in the garden, windburn can be reduced by

• wrapping the plant in burlap during the winter (Figure 11-21).

• applying antitranspirants in the autumn and again in late winter to reduce water loss from the tissue.

The use of anitranspirants is more practical for large evergreens than wrapping. In very cold regions, both techniques may be applied to certain plants.

Damage from temperature extremes Temperature extremes can only be partially guarded against. Where wind chill is a factor, plants should be located in a protected area. Burlap wrapping also helps, especially with hardy species that have tender flower buds.

Certain plants, such as roses, can be cut back in the autumn and their crowns mulched heavily to insulate them against the effects of winter. Similarly, any plant that can be damaged by freezing and thaw­ing of the soil should be heavily mulched after the ground has frozen to insulate against premature thawing.

figure 11-21. Burlap shields protect broadleaved evergreens from winter windburn. (Delmar/Cengage Learning)

To prolong the life of annual flowers in the autumn, when a frost is forecast, the foliage can be sprinkled with water prior to nightfall. The water will give off heat as it changes from liquid to ice and can keep the plant tissue from freezing if the temperature does not go too low for too long.

Sun scald Sun scald of transplants lessens as plants grow older and form thicker bark. Wrapping the trunks of young trees with paper or burlap stripping can provide an effective protection during the first year or two after transplanting. For other types of sun scald, such as that which affects broadleaved evergreens, the same remedies practiced for windburn and temperature extremes are effective.

Some sun scald can be avoided by the landscape designer. Vulnerable species of plants should not be placed on the south side of a building, nor should they be placed against a white wall that will magnify the sun’s effect on the above-ground plant parts.

Heaving Heaving of the turf is impossible to prevent completely. The best defense against it is to encourage deep rooting through deep water­ing, properly timed fertilization, and correct cutting. Bulbs, groundcov – ers, and other perennials can be protected from heaving by application of a mulch after the ground has frozen. The mulch acts to insulate the soil against surface thawing.

Damage from ice and snow Ice and snow damage to foundation plants can be avoided if the designer is careful not to specify plants beneath the overhanging roof line of buildings. If the groundskeeper must deal with plants already existing in an overhang area, the use of hinged wooden A-frames over the plants can help protect them (Figure 11-22). As large pieces of frozen snow and ice tumble off the roof, the frame breaks them apart before they can damage the plants.

To aid plants that have been split or bent by heavy snow accumula­tion, the groundskeeper must work quickly and cautiously. A broom can be used to shake snow off weighted branches, but this must be done

figure 11-22. Hinged wooden A-frames protect foundation plantings from damage caused by sliding ice and snow. (Delmar/Cengage Learning)

gently and immediately after the snow stops. If the branches are frozen or the snow has become hard and icy, removal efforts may do more harm than good.

If plant breakage occurs during the winter, the groundskeeper should prune the damaged part as soon as possible. This reduces the possibility of further damage to the plants during the remainder of the winter.

Large and valuable plants in the landscape can be winterized in the autumn by tying them loosely with strips of burlap or twine (do not use wire). When prepared in this manner, the branches cannot be forced apart by heavy snow, and splitting is avoided.

Damage from animals Animal damage can be prevented either by eliminating the animals or by protecting the plants from their feeding. While rats, mice, moles, and voles are generally regarded as offensive, plantings are damaged as much or more by deer, rabbits, chipmunks, and other more attractive kinds of animals. Certain rodenticides may be employed against some of the undesirable animals that threaten the landscape. In situations in which the animals are welcome but their winter feeding damage is not, a protective enclosure of fine mesh wire fencing or a hard plastic coil around the plants helps to discourage ani­mals from feeding there (Figure 11-23). Nontoxic liquid repellants can also be applied to the base of trees and shrubs in the fall to discourage animal feeding.

Damage from salt Salt injury to turf adjacent to walks can be mini­mized if caution is exercised by the groundskeeper. Salt mixed with coarse sand does a better job than either material used separately and reduces the total quantity of salt applied. The sand provides traction on icy walks, and a small amount of salt can melt a large amount of ice.

Damage from snowplows Snowplow damage is to be expected if plants are too close to walks and roadways. Therefore, when plan­ning landscapes for snowy climates, the designer should avoid placing

figure 11-23. A plastic coil around the trunk of a young tree can protect it against girdling by rabbits and rodents. (Delmar/Cengage Learning. Photo by Jack Ingels.)

shrubs near intersections or other places where snow is likely to be pushed. Another type of damage results from the plow driver’s inability to see objects beneath the snow. If possible, all plants and other objects that cannot be removed for winter should be marked with tall, colored poles that can be seen above the snow. Whenever possible, snow blow­ers should be used instead of plows. These machines are much less likely to cause damage.

Rutting of lawns Rutting of lawns usually results from cars parked there. The best solution to the problem is to avoid the practice. Otherwise, sawhorses or other barriers offer a temporary solution.

SUMMARY______________________________________

As important as the design and proper installation of landscape plant­ings is the ongoing maintenance of the plantings.

Watering must promote deep root development to establish new transplants successfully. Later, watering must be sufficient to keep the plant healthy throughout the growing season. Not all plants require the same amount of water. Infrequent, deep watering is preferable to fre­quent, shallow watering.

Fertilization of trees and shrubs promotes healthier and more vigor­ous growth. Generally, they are best fertilized in the spring when they can take full advantage of the nutrients and still harden off before winter arrives.

Mulching, edging, pruning, and pest control are also important parts of a professional maintenance program. Pruning is the removal of a portion of a plant for better appearance, improved health, controlled growth, or attainment of a desired shape. To prune properly, landscap­ers must understand the structure of trees and shrubs, when to prune to accomplish the desired objective, what and where to cut, and the appropriate tools to use.

Flower plantings are labor intensive, requiring much hand work to keep them attractive. Herbicides and mulch can help control weeds. Frequent watering, midsummer fertilization, and pinching are also necessary.

Winter injury can be due to either natural causes (windburn, tem­perature extremes, sun scald, heaving, ice and snow, or animals) or human error (salting, snowplow damage, or rutted lawns). Certain types of injury can be reduced or eliminated by properly winterizing the land­scape during the preceding autumn.

ACHIEVEMENT REVIEW

3. Place Xs in the following chart to compare the advantages and disadvantages of pruning during different seasons.

Characteristic

Spring

Summer

Autumn

Winter

A full view of the plant’s branching structure is possible.

View of the plant’s branching structure is blocked.

Dead branches cannot be detected.

The timing may conflict with more profitable activities.

The most time that allows for cuts to heal.

This is the best season to prune for the good of most plants.

This is the best season to prune shrubs that flower in early spring.

Plants may be damaged by unintentional breakage.

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?

6. Indicate a maintenance technique that will reduce or eliminate the following types of winter injury.

a. windburn on coniferous evergreen trees

b. a flowering shrub that fails to bloom in the spring

c. roses that exhibit long-dead canes every spring

d. young trees that show sun scald in the spring

e. bulbs and groundcovers that heave to the surface and dry out during the winter

f. tall shrubs that are split by falling ice

g. young trees girdled by rabbits

h. small shrubs broken by a snowplow because the driver was unable to see them

C. ESSAY

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.

KEY TERMS

holdfasts

espaliers

SELECTING AND USING VINES IN THE LANDSCAPE_____

Vines are plants with a vigorous central lead shoot and a long, linear growth habit. They do not grow naturally into clumped, shrub-like forms and are seldom able to grow upright without support. They may be either woody or herbaceous. Vines are among the most versatile plants that can be selected for use in the landscape. Given the opportu­nity to climb, they form interesting walls for the outdoor room. Allowed to trail, they carpet the outdoors with rich and varied textures. If trained to grow on a trellis or along a fence, they can be controlled to create various effects envisioned by a designer. Left to grow naturally, they lend charm and softening qualities to a landscape that might otherwise appear too contrived. Vines are especially useful where height is needed from a plant, but a narrow planting space makes trees or shrubs impossible. Table 9-5 in Chapter 9 lists some of the more common vines available for use in landscapes.

figure 12-1. How vines climb (Delmar/Cengage Learning)

Vines climb in one of three ways depending on the species (Figure 12-1).

1. Some climb by twining themselves around a trellis, fence, or another plant.

2. Others produce fine tendrils that wrap around the supporting structure and allow the vine to climb.

3. Still other vines produce holdfasts that permit the plant almost to glue itself to the support.

A landscaper should be aware of the climbing methods of each spe­cies being considered for use in the landscape before making a final selection. Damage to buildings can result from excessive moisture reten­tion caused by vines growing against an unsuitable surface or from pit­ting of the surface by the vine’s holdfasts.

As with trees and shrubs, vines can be deciduous or evergreen, flow­ering or nonflowering, dense or sparse. Many people avoid using vines because of their maintenance requirements. They do require some spe­cial attention if maximum flowering is to be obtained or if vigorous growth is to be kept under control. However, to avoid their use is to deprive the garden of one of its most contributive elements (Figure 12-2). Factors to consider when choosing vines include:

• Hardiness: Does the vine need a sheltered location or can it survive an open location?

• Sun orientation: Although many flowering vines will survive on a north-facing wall, they do not flower satisfactorily and their vegetation may be sparse.

• Amount of coverage desired: It is unwise to select a vigorous species where only a trace-work of vine is desired.

• Amount and type of support required: Will a trellis be required or does the species climb unaided?

figure 12-2. Vines contribute an architectural quality to this building. Regular maintenance is required to keep the windows and shutters from being overgrown. (© Nathan Guinn, 2009. Used under license from Shutterstock. com)