Espalier is an ancient horticultural method of training a tree or shrub to grow flat against a wall, fence, or trellis. This technique transforms woody plants into two-dimensional, living sculptures. Historically, the practice maximized fruit production in limited spaces and cooler climates by positioning the plant against a warm, sun-exposed surface. Today, espalier is popular for its decorative value and its ability to deliver high yields from fruit trees in small urban gardens.
Selecting the Tree and Site
The success of an espalier begins with choosing the right plant material, ideally a young tree grafted onto dwarfing rootstock. Apple and pear trees are the traditional and easiest subjects to train because their new growth is flexible. Spur-bearing trees, which produce fruit on short, long-lived spurs rather than on branch tips, respond predictably to the precise pruning required for espalier.
The chosen site must provide adequate sunlight, which typically means a south or west-facing wall in the Northern Hemisphere. If training against a solid structure, ensure the area has excellent drainage, as espaliered trees do not tolerate standing water. When planting near a wall, the trunk should be positioned six to eight inches away from the surface to allow for air circulation and prevent the tree from overheating in direct sun.
Building the Support Structure
A permanent support structure is necessary to hold the growing branches. This infrastructure should be built before planting and must be robust enough to support a mature, fruit-laden tree. For a free-standing espalier, sturdy posts, often set in concrete, anchor the framework.
Galvanized wire, typically 12 or 14 gauge, is strung horizontally between the posts or attached to a wall using eye bolts and turnbuckles. These wires are spaced evenly, usually 12 to 18 inches apart, defining the tiers of the design. Turnbuckles allow the gardener to periodically increase the tension, ensuring the wires remain taut as the tree grows and applies pressure.
Establishing the Basic Form
The initial training begins immediately after planting with a cut to the central leader of the young whip. This “heading cut” is made just above the height of the first horizontal wire to stimulate the growth of three buds below the cut. Two buds will form the first pair of horizontal branches, and the third will become the new vertical leader.
As the new shoots develop in the spring, the two selected lateral branches are gently tied to temporary canes angled upward at about 40 degrees. This angled position helps to maintain the vigor of the side branches. Once the growth rate slows in late summer, these branches are carefully lowered and tied to the permanent horizontal wire to establish the first tier. The new central leader is then allowed to grow vertically until it reaches the next wire, where the process is repeated to form the next tier.
Seasonal Maintenance and Refinement
Once the basic framework is established, annual maintenance is required to maintain the flat form and encourage fruit production. Structural pruning occurs during the dormant season, typically in late winter or early spring, to remove dead wood and make corrective cuts that reinforce the desired shape. This heavier pruning is also used to selectively thin out any old or congested fruiting spurs.
The most frequent care involves summer pruning, which manages excessive vertical growth and restricts the tree’s vigor. New side shoots growing from the horizontal branches are cut back to two or three leaves above the basal cluster, encouraging the formation of new fruit spurs. Any subsequent growth is pruned back further, often to a single leaf, to maintain the two-dimensional profile. Regularly check the ties used for training and replace any that are cutting into the bark.