Espalier is the horticultural technique of forcing woody plants to grow flat along the same plane as a wall or fence. This is achieved by systematically pruning branches to restrict plant growth and guiding the branches in a selected direction until the plant assumes the desired shape. The plant is anchored to its companion wall (fence), or else to a trellis running parallel to the wall, via an elaborate support system that serves as a framework.
Fruit trees are among the most suitable plants for espalier because many have flexible lateral branches. The dwarf fruit trees make some of the best espaliers, especially dwarf apple trees (Malus spp.). As with any plant project, make sure your selection is suited to your zone.
Espalier has both aesthetic and practical purposes. You can use this art form to dress up a blank masonry wall, especially if you select a plant with nice flowers. Growing an espalier along a chain-link fence can give you more privacy. In a yard where space is at a premium, an espalier serves as a great space-saver. Running along a solid, south-facing wall, an espaliered plant can enjoy a microclimate where temperatures are warm enough to extend the growing season. Finally, because the dimension of depth has been almost totally eliminated (an espalier has height and width, but no depth to speak of), each leaf of a fruit tree can receive full sunshine, meaning better fruit production per square inch.
When to Espalier
Begin an espalier when the plant is still young. This is when the plant will be most agreeable to taking on the shape you wish to give it, through pruning. The best time to buy the tree and plant it is spring or fall. Buy a plant that is small, so that, as it grows and branches out, you will have the opportunity to selectively prune off branches and thereby control the shape that the plant will take.
Espalier is an ongoing procedure, but, once the espaliered plant has matured (5 to 10 years) and assumed its basic shape, the remaining work is easier and simply a matter of maintenance.
This maintenance consists of pruning three times a year to remove unwanted branches:
- Early spring
- Early summer
Do not prune in late summer or in fall. This would only encourage tender growth that will not be sufficiently hardened off to survive winter, thereby inviting damage.
Styles, Shapes, and Supports
There are different styles and shapes to choose from when creating an espalier. Some gardeners prefer a highly formal style (where the plant is trained to assume a precise pattern). Others like an informal style.
Within these styles, there are also variations; in the formal style, you must decide how many levels or "tiers" (main branches spreading left and right from the trunk) your espalier will have. This decision can be influenced by how tall a wall you have behind the espalier: For a very tall wall, you may want to have more tiers, since this will give you better coverage.
You must also decide on a way to support an espalier. One option is to build out a framework directly from the wall. There are specialty supplies available for working with masonry (for example, concrete nails). For a wooden wall, screw eyes can be effective. You would then string 9-gauge wire between the nails or screw eyes to establish the lines for your tiers.
But it is easier to erect a separate trellis. This way, you will not have to worry about damaging your wall. Besides, a trellis has openings in it, through which you can easily thread ties that will bind the branches to the supporting framework.
What You'll Need
- Tape measure
- Carpenter's level
- String level
- Circular saw, jigsaw
- Drill, screws
- Hammer, nails
- Garden hose
- Suitable plant
- Two stakes
- Scrap lumber
- Two 4 x 4 pressure-treated posts, 8 feet long
- 4 x 8 wood lattice panel
- 1 inch x 8 inch x 8 foot board
- Quick-setting concrete
Twist-ties can serve both to anchor branches to the framework and to mark projected growth (by tying them to the framework to plot out where you want the plant's branches to grow eventually). Not only are they versatile, but they are also free (recycle the ones you have used to tie grocery bags). Stretchy plant ties do exist that are safer to use because they will not girdle branches, but they cost money. If you do not wrap twist-ties tightly around branches, you can avoid girdling.
In our example, we will create a highly formal espalier using a dwarf apple tree, and we will give it three tiers. For a support, we will attach the espalier to an 8-foot-long lattice trellis.
Choose a Location
Because we are growing an apple tree, we need a location with full sun and well-drained soil.
If the trellis is to parallel a wall, locate the trellis 18 inches out from the wall. Sink your 4x4 posts 3 feet down into the ground, pouring concrete into the holes to secure them there. For further stability, attach the 1x8 board across the faces, at the top, of the 4x4 posts. Attach the lattice to this supporting structure.
Using twist-ties, mark the future course of your espalier out on the lattice. We want our apple espalier to be 4 feet high and 7 feet across. So, vertically, run twist-ties 4 feet up from the ground; this is where the trunk will grow. Measure 16 inches up from the ground; this will be the height of our first tier. Run twist-ties, horizontally, 3 1/2 feet out from the vertical column at this 16-inch height, on both the left and the right. Repeat for the second and third tiers. Each tier is separated from the next one by 16 inches.
Install the Plant
Dig a planting hole in front of the vertical column that you have just marked out and place the tree in it. Other than this alignment, installing a plant for espalier is no different from installing any other plant. Add compost as you backfill; add mulch at the end.
Prune the Trunk
"Topping" is usually a dirty word, but not in this project. Prune off the top of the trunk 1 to 2 inches above the first tier, just above a bud. There should be three buds or more below this bud. The idea is to generate side-growth that will become the first tier.
Create First Tier
Once this side-growth has been generated, keep the best branch growing horizontally to the left and the best branch growing horizontally to the right, and prune off the rest. In fall, carefully bend the branches into position so as to form your first tier. Gently tie them to the lattice with twist-ties, avoiding girdling.
Do not make heading cuts on your lateral branches until they've grown out to the final length you want them to achieve. Once they've achieved this length, make heading cuts to stop further growth.
While you're waiting for this lateral growth, don’t let the trunk reach more than 6 inches above the first tier; if it does, prune it to keep it "in-bounds."
Create Second Tier
After your first-tier branches have made it 3/4 of the way across to their projected terminal point, let the trunk grow to the second tier, and repeat the process you used to make the first tier.
Create Third Tier
Do the same to create the third tier.