Among the horticultural contrivances of gardeners over their centuries of cultivating ornamental plants are espaliers. Espaliers are trees and shrubs that are allowed to develop only two dimensionally: they have height and width, but hardly any depth (Figure 12-3). In appearance, they may suggest a vine to the viewer because of their flatness. Whereas vines are a natural growth form of plants, espaliers are entirely created by gardeners and must rely totally on continuing human attention to exist in their unusual form.

Espaliers were originally developed as a way of incorporating into gardens desirable fruiting species such as apples, pears, and peaches without giving them a lot of space. The trees were trained against court­yard walls and along fences. They were even developed inside early or­angeries (see Chapter 20) and in greenhouses. Later, other species were tried and found usable solely for their decorative effect.

Espaliers are most commonly grown against walls or fences for two reasons.

1. The support is convenient and necessary for initial training of the young plant.

2. The wall provides a good background for viewing the plant and its branching pattern. Although a decorative branching pattern is not necessary, it is traditional, and over the years some attractive and clever styles have been developed. It is possible for certain tree espaliers to be free-standing, however (Figure 12-4).

As elements of the landscape, espaliers serve as novelties since they are not commonplace plant forms. If used correctly, they can function as focal points or as accent features against a garden wall. Their uses are similar to those of decorative vines, yet they have a distinctively differ­ent appearance.

figure 12-3. An espaliered fruit tree grows against this brick wall. (© Gary Unwin, 2009. Used under license from Shutterstock. com)

figure 12-4. This espaliered fruit tree is self-supporting. The wires direct and hold the young branches until they mature. (Delmar/Cengage Learning. Photo by Marietta Loehrlein.)