It is no secret that I am very fond of espaliered trees. Espaliers? These are trees or shrubs which are pruned to a 2-dimensional shape. Though the practice dates back many centuries, a French monk, Fr. Legendre, published a book in 1684 entitled “Palmette Legendre”. He detailed his method for drastically pruning fruit trees so they could be grown against the monastery walls. This made it possible to grow many more trees, and harvest more fruit, in a small space. The French word espalier is derived from the Italian word “spalliera”, meaning “something to rest the shoulder (spalla) against”. These fruit trees rested their shoulders against the wall.
Fr. Legendre discovered that fruit trees that were subject to this kind of hard pruning, and enjoying the warmth generated by the wall, produced better yields. The growth generated in the third dimension would be cut back to the fruiting spurs. The first espaliers were pruned to encourage long horizontal arms. It seems that horizontal branches bear more fruit than vertical ones. This horizontal shape is known as a cordon, and is quite similar to how grapes are pruned.
Eventually, many different styles of pruning emerged. Some styles are just as decorative as they are utilitarian. The tree pictured above has been trained into a classic fan shape. All of the primary arms radiate outward from the trunk in the shape of a fan. This shape is great for a wall that is both tall and wide. Blank walls in the landscape are a perfect spot for an espalier. The pattern of green, light and shadow that the tree creates provides interest in a spot that is otherwise empty. Should I under plant an espalier, I like like a short growing plant. Part of the beauty of an espalier is being able to see the entire shape, from top to bottom.
Espaliers are traditionally created from fruit bearing trees. Though apples prefer a sunny location to fruit well, a pear tree is fairly tolerant of a shady location. I am partial to pears. Their glossy leaves are beautiful, and they seem more resistant to fungal problems. Many fruit trees require another tree for cross pollination. If you want to grow an espalier for fruit, be sure you grow a pair, or pick a variety that is self pollinating. All fruiting trees are beautiful when they bloom in the spring. An espalier fruit tree in full bloom is especially gorgeous, as the white flowers dramatically detail the geometry of the shape.
These four espaliers are Kieffer pears, trained in the candelabra form. It is easy to see here that an overall form has been determined for the large branches. Once a horizontal branch reaches the width desired, the young branch is turned towards the sky, and tied to a form. That branch will require support until it gets enough to stand on its own. Pear wood hardens off quickly. If you are training an espalier, be sure to make any change in direction when the branch is still very young. Barely visible at the top of this picture is a horizontal fish line. The branches are tied to this to keep them vertical, and keep them the desired distance from neighboring branches. We have secured the branches in this manner for display only. Once they are planted against a wall, galvanized steel eyes will need to be installed in the mortar. The branches will be tied to those eyes using a flexible and expandable landscape tie.
Though a fruiting tree is a traditional subject for an espalier, lots of trees and shrubs readily take to this kind of pruning. Pictured above is a white rose of sharon, trained into a fan. The picture is not the best. Imagine many branches emerging from the soil in a line., rather than a mass. Any branch which emerged from the ground outside of the line-either to the front or back-was removed. The fan is created with many branches, rather than just a select few. This shape of this shrub reminds me of fan coral. It will be a solid mass of green, in leaf-and a solid mass of white in flower.
A Belgian fence is a series of espaliered trees that are planted equidistant from each other. Each interior tree has a single trunk which comes up up out of the ground about 18″. Years ago, that trunk was pruned down to 18″. A pair of emerging side shoots were trained at a specific and repeating angle. The collection of trees produces multiple diamond shapes. Ideally, each diamond is the same size as its neighbor. Maintaining the diamond shapes requires faithful and regular pruning. The larger and simpler the diamonds, the easier the care. This group of trees are Calloway crab apples. They have a beautiful cinnamon colored bark, and flower and fruit like all crab apples.
The large espaliers in this picture are lindens-old lindens. The cordon espaliers in front of them-Bradford pears. Both species are ornamental, and tolerate hard pruning. These trees may also be allowed to fill in between the horizontal layers. This would result in a solid thin wall of green. They could be grown against a wall, or as a freestanding green wall. Any espalier which is grown as a fence will need lots of support and direction in the early years. Big bamboo stakes are prefect for this. The bamboo you see on the foreground trees was attached to keep all the branches in place during shipping.
This espalier has been grown in a goblet shape. The change in direction from a horizontal to vertical is a gently curve, as opposed to the right angle of a candelabra style. As the main arms are fairly well established, we only needed to secure the tops of the branches to keep the tree representing its intended shape.
These fan espaliers are apples and pears of various varieties. A whole orchard could be grown in a relatively small space. Training espaliers is an art form, but a form that can be learned. As slowly as trees grow, you would have time for your knowledge to grow. A large caliper espalier is an investment, mainly due to the years it took to get it to size. This particular grower does not sell any trees unless they are at least 7 years old. Over the course of that 7 years, he waters and feeds, and keeps the yellow bellied sapsuckers from drilling holes in their trunks. He has trees that have had a major arm die back-heartbreaking this. But once an espalier is established, they are no more care than any other tree or shrub. Some nurseries and garden centers carry 1-2 year old plants. This makes it easy to give one a try.
Would not the silhouette of this tree, trained and grown parallel to a wall, get your attention? Even out of leaf, it is striking. You are looking at an espalier- a tree trained to grow in only two dimensions. In the late 1600’s, Fr. Legendre, a monk living in Hanonville France was in charge of his monastery’s garden. His fruit trees were bedevilled by late frosts that killed the fruiting buds. Noticing that the fruit trees planted closest to the monastery walls sustained the least damage, he began planting his fruit trees as close to the walls as possible. As wall space was limited, he began shearing his trees, so as to provide room for all the varieties he wanted to grow. Amazingly, the drastically sheared trees produced heavier yields than unpruned trees in the field. His book, Palmette Legendre, was published shortly before his death in 1684. This book is the earliest known text regarding the science of growing espaliers. These trees, pruned flat, spare, and parallel to a wall, had fewer cultural problems, took up little space, and were beautiful to boot.
Espaliered fruit trees look like no naturally growing tree . Though no tree expert would advise this kind of planting, pruning and shaping, Father Legendre’s ideas practices enabled ample fruit for everyone living at his monastery. Sometimes the hand of man comes to good end in the environment. This very early spring picture shows an espaliered tree, grown in the candelabra shape. It would be beautiful, grown on a blank wall-never mind the fruit. Training trees to grow in two dimensions became a gardening art form-even for those who had no need to feed many from a very small plot of land. 
I make a special effort to offer exceptional espaliered trees to my clients. My grower of choice is of French descent, and his espaliers take my breath away. I drive a day’s length to see and review his espaliers. He grows in the traditional way, and only has a few trees to offer for sale every year. He sells no trees that are not at least seven years old; his big trees are much older. He pots his trees, and then sinks the pots in the ground. Note that the trunk of this tree is positioned to the back of its pots-his trees are easy to plant close to a wall. 
Their winter appearance is architectural. The American landscape is fundamentally based on big spaces; we have eight lane highways and driveways 22 feet wide. This makes this particular dose of French editing all the more refreshing. People who come to my store are invariably interested in their history and forms.
My grower trains some of his espaliers in a form not existing in the classical literature. This framed heart is entirely his invention; how I love this. It has a distinctly American feeling; he has taken his classical training, and gone beyond. 
This informal heart espalier enchanted one of my clients. I call it the wild at heart espalier. As she had no room in the ground, we built her a box for her deck, insulated to slow the freeze, and delay the spring thaw; this apple tree is thriving. We heap up the compost after the ground freezes, and we uncover it in the spring; so far, so good.
Not all espaliers are fruit trees. The art of training espaliered trees has extended to many trees tolerant of this treatment. This Bradford pear makes a big statement as an espalier. Any lonely wall would be all the happier for this tree planted on it.
This series of trees is known as a Belgian Fence. You can see that individual trees were topped low to the ground as whips, encouraging branching in both directions. The branches of these trees are trained in a diamond pattern; what a beautiful living ornament for a long wall, or a free standing fence.