Espaliering means training a tree or shrub to grow against a wall or a fence so a flat, two dimensional effect is achieved. It's a technique that was very popular in the Middle Ages in Europe because it allowed fruit to be grown inside the walls of castle courtyards, without encroaching on the open space. It also has a lot of modern appeal as a way of saving space in a small courtyard or narrow area - and it's a lot of fun to try.
There are some trees that are particularly suited to this style of training - Apples and pears were traditionally used and crab-apples work well too, with their pretty blossoms. If a Mediterranean look is preferred, use olives, citrus and sasanqua camellias also work well. Almost any tree, or even climbing plants, can be espaliered into a simple design.
There are many different shapes that an espalier can take - fan shapes, U shapes, informal patterns or more intricate diamond patterns. One of the easiest methods is to create a simple horizontal espalier. This is where the lateral branches run horizontally at regular spacing along three or so wires.
Sasanqua camellias have pliable branches, thus lending themselves to being espaliered and they are also evergreen with spectacular flowers. The Camellia can be trained onto a fence, a trellis or create a free-standing wall. Frames can be purchased to make the task simpler.
How to Espalier
Fasten some wires to the fence with some simple eye bolts, spacing them approximately 30 cm apart or wider, depending on the design and the plant that is being shaped. Wires need to be tense, preferably with a turn buckle so the tension of the wire can be increased if it sags over time with the increasing weight. Place them at least 10cm out from the wall, to allow for good air circulation between that and the plant.
Choose a plant that has a nice open growth habit and several leading branches. Match up the plant to the wires and look at it carefully, choosing the lateral branches to be retained and prune off all other laterals near the trunk. Basically, the branches which cannot be fitted into the pattern need to be removed. Tie the braches firmly down to the wires. Ties are needed about every 20cm. Use flexible ties which should be checked regularly and loosened to avoid damage to the stems. Prune the tips of the branches back to the desired length, to a bud.
Espaliering is a high maintenance technique, but when it's done well, the results are often spectacular. Once all of the early training to get the right shape is done, it will need to be maintained with regular pruning - approximately three times a year. If espaliering a deciduous fruit tree, then the serious pruning or shaping needs to be done in the winter. Sasanqua camellias flower through autumn and into winter, so leave any heavy pruning until after they finish flowering, so the blooms are not sacrificed.
Not only are espaliers great space-savers but with a little bit of time and effort, they make a fantastic feature in the garden and a great way to liven-up a tired old fence!