Espalier is a strange topic. Either you’ve never heard of it, you’re too intimidated to try your hand at it, or you’re obsessed with it. There isn’t much gray area on the subject.
Those of you in the first category may be wondering: What is an espalier, anyway? At its most basic, an espalier is a small fruit tree or bush trained to grow flat on the side of a building, along a fence, or as a fence or screen. Technically, espalier (ess-PALL’-yay) is the method of training the tree into growing in a flat form, not the tree itself. But most people call the whole thing an espalier, a bit like a bonsai tree. Espaliers are typically found growing against medieval castle walls, in estate conservatories, or in the backyards of Master Gardeners. You could make the argument that a grape arbor is a kind of espalier, although most espaliers are more structured and formal.
Espalier is fundamentally a formal training style, but because the basic materials are living woody plants, there are almost as many patterns and forms as there are espalier. The form you choose can be as rigid and formal or as whimsical and fantastical as you wish. I have two European pear trees trained as four-tier horizontal cordons, and I’m getting ready to plant an Asian pear that’ll be trained as a candelabra form. Search online for the key words “espalier form” or “espalier pattern” for a wealth of ideas, and modify the form you choose to suit your fancy and your growing situation.
Plan for Success
Keep the type and size of your plant in mind when you choose your espalier form. I made a rookie mistake when I chose two European pears on semidwarfing rootstock for a 12-foot area — a space big enough for just one semidwarf. Fifteen years later, I still struggle to get them to flower, while they still struggle to grow larger. I’ve learned my lesson, though, and the Asian pear will have twice as much space in which to spread and fruit.
Semidwarf trees need a minimum of 10 feet of wall space to grow, full dwarf trees can be comfortable with 6 feet of space, and small-fruit bushes, such as currants, fit nicely in 4 to 6 feet. These suggestions assume wall space and room for multiple branches; training along a single fence rail will require at least double the linear space. Heavily planted forms, such as Belgian fences, require full dwarf trees, as each individual tree has only two branches growing in a “V” laced together with its neighbors.
The type of tree you want will also affect the pattern you select. Apple and pear trees do well in uniform, classic patterns, such as the horizontal cordon or candelabra. Cherries and stone fruits are better suited to more forgiving, informal patterns, such as the free-form or informal fan.
Next, you need to consider support. Support does several things: It keeps trees from falling over; it provides a pattern to plan against and a place to tie young branches, and it creates a boundary to limit the final size of the trees. Espaliered trees need support for their entire lives, so you’ll need to build to last. Plan on using heavy steel posts and sleepers — short posts driven into the ground at an angle, used as anchors for a guy line (see “Steel Post Diagram,” below). Or use pressure-treated 4×4 posts with sleepers or a doubled 2×4 crossbeam (see “Braced Wood Diagram,” below). Run rust-resistant wire between the posts at 12-to-18-inch intervals, with turnbuckles installed to maintain tension. I use black-rubber-jacketed stainless-steel telecom wire for my frames, but galvanized high-tension wire or heavy-gauge electrical fence wire will also work.
Locate the trellis 4 to 12 inches away from the backing wall. Another option available if you have brick, block, or stone walls is to use 4-inch (or longer) eye bolts tightened into lead masonry anchors. This is a permanent method and has a pleasing aesthetic, but it’s also destructive. If you don’t want to drill into your home’s masonry, use a free-standing trellis frame.
Split-rail fencing also serves well as an espalier frame, creating a picturesque garden fence. A two-tier horizontal cordon pattern centered between each post is ideal for this form. Another variation of an espaliered fence is the step-over pattern. This is a single-tier horizontal cordon trained to be no more than 12 inches above the ground, creating a fence line you can step over, hence the name. This will also need support, only closer to the ground. A step-over espalier will also need more room per plant than a more complex pattern; expect to increase the linear feet per tree by an extra 50 percent. For example, a dwarf apple tree may reach 9 feet wide on a step-over when it would only reach 6 feet on a four-tier horizontal or a fan.
Plant, Position, and Prune for Pattern
Once you’ve selected your desired pattern and worked out the support details, you’re ready to plant your trees. Locate the spot where you want the tree on the espalier support. Dig the planting hole only as deep as the root ball, but twice as wide. Set the tree at least 4 inches from any backing structure, or better yet, 12 inches away. Settle the tree in place, spread its roots out into the planting hole, and backfill with the native soil removed when digging the hole. (When backfilling, be sure to plant the tree only as deep as it was in its pot.) Don’t add compost or enriched soil to the hole, so the roots are encouraged to stretch out in search of nutrients, creating a stronger root network and base. Water the tree well, rocking it gently by hand as you water to settle it in securely and eliminate air pockets around the roots.
Tie the tree loosely to the bottom wire of the frame with soft twine or discarded nylon stocking material. The next step is difficult emotionally, but necessary for achieving the form you want: Cut the top of the tree off, leaving 3 to 5 well-placed buds at, or just below, the bottom wire and pointing in the desired directions. When you do this, make certain the buds you select are above the graft union of the tree. Cutting off everything above this point will encourage the buds to grow into new branches.
New shoots grow best when they’re allowed to grow vertically; the closer to horizontal they grow, the slower they grow, and they’re more prone to send out new vertical shoots. Take advantage of this by letting each new shoot grow vertically for a week or two, then gradually shift its position from a vertical direction to its final placement. Take your time repositioning the branch; impatience leads to a snapped branch and starting over with a new bud. Tie a thin bamboo stake loosely to each new shoot like a splint, and tie the stake to the espalier wires. Every few days, shift the splints to a more horizontal position. The shoots will continue to grow upward at the tips as you lower them into place. As this occurs, tie new bamboo to the ends of the shoots and the wires, slowly moving them into place as well.
Expect this process to take several years. For example, each tier of a four-tier horizontal cordon will take a year’s growth. Each vertical shoot on a candelabra will take a year’s growth for placement, then another year for each 18 inches of vertical growth. A step-over may produce up to 3 feet of growth in a year.
Patience is in order for the initial training period. Be prepared to change plans as buds break into growth or refuse to grow. For instance, the bud that was supposed to develop into the main trunk of my ‘Anjou’ pear at the first tier failed to do so. I allowed the first vertical bud on the left horizontal branch to develop into a new shoot to replace the original vertical. For a few years, I could see the slight leftward shift in the trunk. Now, I can’t even find the shift.
There will also be buds growing in the wrong place, or the wrong direction. If a new bud breaks in a direction you don’t want, allow it to grow 3 to 5 leaves, then pinch out the growing tip. This is an important step that needs to be done throughout the growing season. (It’s also a pleasant way to spend a Saturday morning.) The best tools for this kind of pruning are your index finger and thumb. The tender new growth will snap easily with just a little pressure, or you can use your thumbnail to cut the shoot against the pad of your finger. Because you’re making slight pruning cuts throughout summer, there’s little or no need to prune your espalier in winter. In fact, that’s the major management difference between espalier and standard tree pruning: summer pruning as opposed to dormant pruning.
Once the tree has grown into its final form, the aim of pruning changes from directing growth to promoting fruiting. Fruiting buds usually form on either horizontal or hanging branches, and rarely on vertical growth. Keep this in mind as you hand-prune, a task you’ll do regularly throughout the season. As a bud develops into a shoot, let it grow 5 to 7 leaves, then pinch it off just beyond a downward or outward pointing bud. If the shoots insist on growing vertically, you can coax them into a more horizontal direction by carefully flexing the new shoots. Done properly, this breaks up hardening woody tissue without snapping the shoot. You should be able to feel the tissue fracturing as you flex it. Afterward, the shoot will droop, and the fractured tissues will heal in the new position. If you snap one or two at the beginning, don’t worry. More will grow.
If a shoot gets excessively long (over 12 inches) while you’re not looking, you can try another technique: Carefully flex the shoot to fracture the tissues, then loop it into a loose knot. Next year, you should have fruit buds forming only below the knot, as sap doesn’t like to flow in a circle.
Keep a few things in mind as you prune. Don’t be afraid to take out shoots that are poorly placed. Don’t prune when the shoots are damp, as that can spread disease. Stop pruning by mid-to-late August, so any new growth stimulated by the pruning has a chance to mature and harden off before the last frost. Finally, don’t worry if your espalier starts to get a little shaggy. Just prune a little harder, and remember, you’re not being judged on how tidy it is.
Once your tree begins to blossom and set fruit, fruit thinning becomes important. Allow enough space between each fruit for them to grow to full size without touching their neighbors. Prune excess leaves away from each fruit so sunlight can reach it and ripen it to perfection. It’s true, you won’t get as big a harvest from an espaliered tree as from a free-standing tree, but the individual fruit quality will be better, thanks in part to the extra attention each fruit will receive as you prune the tree throughout the season.
Take your time looking at espalier forms and examining your property. Decide what fruit you want to grow, and what form you want to grow it in. Build the frame to last. Pay attention to how your tree grows, and how to coax it to grow where you want it to. Get ready for lots of questions from visitors, and for a certain amount of amazement. Before you know it, you’ll have gone from “afraid to try it” to “local espalier expert.” And maybe you, too, will become a little obsessed with espalier.
Andrew Weidman lives and writes in Lebanon, Pennsylvania. He’s vice president of the Backyard Fruit Growers, a grassroots group dedicated to helping people grow their own healthful fruit. Andrew has been training his pear espaliers for the past 15 years.