Espalier (ess-PAL-yay) gardening is the ancient horticultural art of training trees, vines and shrubs to grow into a 2-dimensional pattern against and along a trellis, fence or solid wall.
Adding a fruit tree espalier to your garden or landscape will add a dramatic, living, and tasty focal point that can last more than a decade with minimal care and maintenance.

The word espalier is French, and it comes from the Italian spalliera, meaning "something to rest the shoulder (spalla) against."  During the 17th Century, the word initially referred only to the actual trellis or frame on which such a plant was trained to grow, but over time, it has come to be used to describe both the practice and the plants themselves.

Plants are frequently shaped in formal patterns, flat against a structure such as a wall, fence, or trellis. According to American Garden History, espalier was originally used to create outdoor "walls" in Europe during the Middle Ages, and was also planted in interior courtyard walls to prevent late spring frost bud-kill. The practice also allowed the cloistered residents of warring cities to feed themselves without venturing beyond the safety of their walled compounds. Other records show this technique dates back to ancient Egypt, where hieroglyphs of espaliered fig trees have been found in tombs dating back to 1400 B.C.

Vintage artwork from medieval illuminated manuscripts

Espalier are ideally suited to small spaces. Perfect for terrace gardens and courtyards. I like to call it a horizontal fruit garden design.
A fun and decorative way to grow lots of fruit trees in a very small space.  And it's very ornamental. You're eliminating the upward and outward growth, so you'll have larger fruit growth and taking care of the fruit trees is very easy. You're not using a ladder and ropes, pruners, and saws and what-have-you. Everything is reachable. And you can spot a bug or disease a mile away. You're allowing airflow through the trees, and that helps reduce your chance of fungal diseases. The tree is entirely tied down, and it's almost flat....so wind damage is almost a thing of the past. A very worthwhile and interesting project. This is a nice project for retirees and folks who would love a fruit tree garden, but find bending, digging, tedious pruning and reaching a physical challenge. It reminds me of the way grapevines are grown in an orchard.

If you don't have a fence, you can still grow an espalier row that will also serve as a boundary around your property. When it fills in, it's a living fence. Dwarf fruit trees produce full-sized fruit on a dwarf rootstock. With an espalier, you can harvest your fruit quickly and easily, and nothing will be wasted or eaten by birds because you have a 25 ft. tree. You will get fruit in much less time,  need much less time pruning to control its size, and be better able to protect your fruit from birds and animals when you're using dwarf varieties of trees. There's a dwarf or semi-dwarf variety of almost every fruit.

There are also structures you can buy, trellises and tunnel forms, that can be used to train trees against and put them wherever you want.

Planning Your Espalier Garden

Espalier are trained to grow against a frame or flat wall having only two dimensions – width and height. Apart from the obvious visual attraction there are three good reasons to find a suitable espalier pattern for your plants :

• You can control growth to maximize fruit production.
• Fruit can be forced to be presented for ease of picking.
• They can be faced southward to absorb maximum sunlight. This extends the growing season.

Some gardeners enjoy growing espaliers that produce fruit because you can get a lot of fruit trees without a lot of space, but you can choose ornamental tree species as well. Choose plants that will branch and spread naturally and that are well-suited to the growing conditions of your location. 
Many gardeners recommend using woody plants or trees grown on dwarf root stock. I'm one of them. Dwarf fruit trees are my espalier choices. Although I would like to take a shot at espalier of an unusual dwarf, like Japanese Maple, with those gorgeous leaf colors and shapes. Other woody ornamentals like lilac and non-invasive wisteria are also good choices.

Walls and Fences - Most espalier is done on wood fences, because you can screw the shaping wiring in and not damage a vinyl fence. But you can work around that, and you can have free-standing espaliers that are grown close to the fence. Or grow them along a wall, by putting  screws or eyehooks into stone, siding, brick, stucco, or wood structures. If you have a vintage metal wire fence, you won't need to make wires to train the trees. Just attach and prune your branches using the openings as the backbone of your design. 

Espaliers can be used to disguise unattractive walls or fences or to screen views ugly areas. Free-standing forms make elegant fences or unique vertical accents. 
Espalier is also used in some commercial orchards to increase productivity.

The intensive pruning directs energy away from vigorous vertical growth into the shorter, lateral fruit-bearing spurs, resulting in heavier yields than on ordinary trees. Because they are less susceptible to breaking branches, espaliered trees can have an incredible life span – some espaliered apple trees are still producing fruit after 150 years. Some other advantages to espaliering fruit trees include being able to grow several different cultivars in the space of a single normal tree, for greater diversity in fruit types and cross-pollination requirements; the trees bear earlier and for a longer time with deeper fruit color.

What To Plant

Use almost any woody tree or tall shrub. The branches and stems will be stronger and more bendable, and won't break as easily as fibrous stems.

While designing a tree presents a challenge, you can take a shortcut by purchasing espalier starts at a nursery. Already shaped and trained on trellising, these can be planted in a chosen spot and their forms simply extended and maintained as they develop.

Apple and pear trees are the traditional espalier subject. because they have supple, easily-trained new growth, but other fruit trees that sometimes are espaliered include fig (Ficus carica), peaches, cherries and pomegranates. Plums, nectarines and apricots require more careful pruning. Dwarf cultivars are easier to train than standard size trees.

Almost any woody plant with long flexible branches can be used for espalier. Ornamental plants such as bougainvillea, camellias, cotoneaster, flowering crabapples (Malus), flowering quince, forsythia, holly, magnolia, Pfitzer juniper (Juniperus chinensis ‘Pfitzerana’), some viburnums, winged euonymous, and witch hazels (Hamamelis) are quite amenable to espalier. Climbing roses could be used, because their natural climbing habit is easy to manipulate.

When planting, place each tree about 6-12 inches from the wall or fence, with its two strongest shoots or branches situated to follow your design. Take your time to ensure your plants are spaced precisely the same distance apart. The best types of plants are established, and about 3-4 ft. tall, or 3+ gallon size, because these will be strong already and take more kindly to constant pruning. When branches are about a foot long, tie them loosely to wires or eyebolts using twine or another material that won't dig into soft stem tissue. Prune annually, in late winter or early spring, before active growing starts.

You can also espalier potted fruit trees. They'll be a little further from the support, but you don't have to plant the trees in the ground. That's my ideal scenario. I have some tall pots with flat sides that will work better than round ones.

Based on your chosen design, string heavy-gauge wire between nails inserted in the wall or fence or through notches cut into the fence panels.

As a general rule fruits that have stones (such as  cherries, mirabelles, peaches, plums, nectarines, apricots, cherries) are best trained as fan patterns. One of the simplest and most effective ways to train a fruit tree is as a U Cordon, sometimes called "Candelabra".

• Cordon – the most traditional form in which branches are trained to grow horizontally out of one central trunk. A single cordon is known as a “rope.” A multi-tier cordon generally has three tiers of branches but could have as many as five tiers. Cordon espaliering can be used to form living fences or to increase yield in small orchards.
• Palmetto Verrier – branches are shaped into a U as the horizontal branches are turned up at the ends. This creates nice definition between trees planted against a wall.
• Fan – branches angled at 45° grow radiating from a central trunk in a fan-shaped pattern. This is best for spaces requiring vertical coverage or in square spaces.
• Candelabra – several vertical branches arise at regular intervals from a low horizontal branch coming off the central trunk, forming a candelabra shape.
• Informal – more naturally shaped, but still in a single plane. This requires only simple pruning.
• Belgian Fence – three or more V-shaped espaliers are woven together into a fence for a lattice effect. The two trees on the ends are modified Vs for finished ends.

Training and Maintaining

When to Prune 

The bending and training of the limbs that will remain in the design is done during the progression of the summer season, when they are most flexible.

While it usually takes about four years to get the full artistic effect of your efforts, you may actually see fruit as soon as the second year. Especially when growing dwarfs, and if you planted a good-sized tree, not just a cutting. The dwarfs will bear fruit much sooner.

You can add several rows of wire or support for height, if you wish. I would keep mine at 5-6 feet tall for ease of care. Unless i want to use a ladder. Which I don't.

Plant a fruit or ornamental flowering tree in the middle.

Select the branches that will form your espalier. Branching should start well below the wire so that you don't damage them when you tie them on the wire. Prune out all other branches.

When branches are pulled below 45° growth slows down. You can use this fact to ensure that branches grow evenly by pulling down longer branches first and leaving smaller ones to grow.