An ancient growing technique and art form, espalier specimens are trees or shrubs trained to a single vertical growing plane and are ideal for small urban lots or in narrow passageways anywhere in the landscape. The most popular type of tree to espalier is a fruit tree. Planted against a south-facing masonry or stone wall, it is possible to grow a variety that is considered not hardy enough for your location, because the reflected heat from the wall will moderate the surrounding temperature. To delay flowering to protect the blossoms from late-spring frosts, plant your espaliered specimen against a north- or east-facing wall.
Choose a place to plant your espalier in front of a wall or fence. The planting bed itself can be as small as 18 inches wide, because espalier specimens are grown in a single vertical plane and their top growth will easily fit in a small space.
Install a support structure by inserting hardware anchor bolts into the fence or wall and inserting eye screws into them. As the tree grows, the branches will be fastened to the eye screws with heavy gauge wire to form it into the desired shape.
Dig a hole twice as large as the root ball of the espalier sapling. Improve the soil removed from the hole by adding 1 to 2 shovelfuls of both compost and peat moss. Mix them together thoroughly with the soil.
Add enough soil to the bottom of the hole so that when the rootball is placed into the hole, the top of it is even with the surface of the soil. Gently firm the soil in the bottom of the hole with your foot.
Remove the espalier sapling from its nursery pot and place it in the hole. Backfill the hole with the improved soil, firming it down gently with your foot as you go.
Make a ridge of soil around the outside of the planting hole, using your hands. This will catch rainwater.
Place a hose with a slow stream of water near the base of the tree and allow it to water-in the tree for about 30- to 60-minutes.
Apply a 3- to 4-inch layer of mulch around the base of the tree of wood chips or shredded bark.
Prune off all side branches below the level at which the first horizontal branches will be trained against the wall. If the sapling is taller than the desired first level of horizontal branches, cut the main leader off about 2 to 3 inches above this level.