Pruning May Take Extreme Forms

Late winter and early spring are the best times to prune plants. Fruit trees, ornamental shrubs, shade trees and many other plants recover quickly and are less subject to injury if pruned at this time of year. However, to prove that plants are able to endure very extreme types of pruning, let us consider some of the most unusual forms.

Over thousands of years living with plants, some bizarre pruning practices have evolved. Perhaps the two most extreme forms that are still used today are topiary and espalier (pronounced ess-PAL-yer. Both these pruning techniques apparently originated in ancient Rome, and have survived with varying degrees of popularity since that time.

Topiary, the art of forming plants into the shapes of animals, people or geometric figures is seldom seen in home landscapes, and only occasionally in public gardens. It made use of evergreen plants such as boxwood and yew to form into animals such as deer, bear, giraffe or geometric figures including cones, cubes, spheres or combination of them. It requires a large amount of hand labor and time to develop and maintain plants in these unnatural shapes. Topiary reached its peak of popularity in the middle 1600’s, but the gradual shift to more naturalistic landscapes and more expensive labor led to its decline.

Espalier, which is still frequently practiced, is a technique of pruning that forces a plant to grow in a flat plane, usually against a wall or trellis. Since this practice goes back to ancient Rome, the word itself is based on an Italian word meaning a shoulder strap. This is because the basic design often suggested a shoulder-like appearance as the branches came from the trunk at right angles and then turned abruptly upright in a candelabra-like shape.

The word we use today is actually a French word which means fruit wall. Espalier reached its peak popularity in France. Colonial Americans also practiced espalier, and George Washington used espaliered fruit trees in his gardens at Mt. Vernon.

Espalier may become more popular with home gardeners once again. Many homes have limited space, and dwarf fruit trees may be espaliered with much less pruning than standard trees. These fruit trees can be both ornamental and productive on a blank wall. An espalier may even help save energy by shading a hot, sunny wall in summer or reduce heat loss by cutting down rapid air movement across a house wall on a windy winter day. Those who would like to espalier flowering plants might consider pyrancantha, spirea, flowering quince, forsythia, magnolia, or evergreens such as yew.

To make an espalier, branches do not have to be pulled tightly against a wall, but may be allowed to remain about 6 inches from it. This will create dead air space as well as provide more suitable temperatures for plant growth. Fasteners or nails placed into the wall are often used to develop the design. Espalier may also be done against a trellis or fence. Tying and shaping against a trellis or fence is easier than shaping with pegs inserted into a wall. Do not tie branches with wire, but use soft string. Wire may bind the branch as it becomes thicker. Even cloth ties should be examined occasionally to prevent girdling of branches. As the form develops, branches will become rigid and need less ties.

Before beginning, draw the geometric design you want to create on a piece of paper and take it with you whenever you pinch or prune the plant. Start with small young plants that are flexible, and do not deviate from the planned design. If a branch becomes too woody to be bent properly, cut it back severely to force out young shoots that can be curved properly.

Severe cuts should be made while plants are dormant. Very frequent clipping out of small twigs may be done anytime during the season as needed. Avoid late summer pruning when late growth might develop that is easily killed by severe winter weather.

• © 1989, International Society of Arboriculture. All rights reserved.