Pleaching: The art of training trees

Once the preserve of grand estates, pleaching – the art of training trees into stunning shapes – has become a modern style statement.

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A tunnel of pleached crab apples Photo: ALAMY

By John Hoyland

7:00AM GMT 26 Nov 2011

Sooner or later all gardeners realise that there is nothing new under the sun. Every trendy planting style, technique and design element is just a reinterpretation of what has gone before. The 26th National Tree Week (www.tree council.org.uk) starts today, and it is a good opportunity to think about how to make old arboreal techniques sing in a contemporary setting.

The use of pleached trees to establish the architecture of a garden is one of the defining aspects of 17th and 18th-century design, particularly in France and Italy. Traditionally used to demarcate grand allées or to enclose intimate spaces, pleached trees had, until recently, fallen out of widespread use. Now, following their appearance in Chelsea Flower Show gardens, often in the form of “hedges on stilts,” enthusiasm for pleached trees is filtering across the country. Related forms of manipulation are also popular – tree “ceilings” and tunnels, for example, can be seen for sale in large garden centres.

Pleaching is a style of growing trees in a line, usually straight, with the branches of the tree tied together and clipped to form a flat plane above the bare trunk. The branches are tied onto canes or wire to make tiers, and are then regularly pruned to keep their shape.Sometimes they naturally graft themselves onto one another.

Planting a pleached hedge has been made much easier in recent years by the availability of ready-pleached trees. Imported mainly from Italy, these are trees whose branches have already started to be trained and are tied to a bamboo frame. Even in this immature state they have an instant and dramatic impact in a garden but, before planting them, it is essential to imagine what they will be like in five, 10 and 20 years’ time. Leave lots of space for them to grow.

An imposing row of neatly clipped trees looks beautiful, but demands work. Head gardener David Martin looks after dozens of pleached trees at the Jardins du Bâtiment in Thiré, France (the country where you will find the best examples of the technique). He estimates that a team of three expert gardeners will spend a whole week, twice a year, maintaining a run of 50 trees.