A pleached hedge is one in which branches have been bent down or interwoven to form a living wall. This very ancient technique was known to the Romans and mentioned by Julius Caesar who saw it used as a military obstacle in Flanders. In Much Ado about Nothing, Shakespeare refers to "Walking in a thick pleached alley in my orchard". In more modern times, it is a technique used by some farmers to make their hedges more secure. Featured left is an avenue of pleached limes (Tilia x euchlora) at Arley Hall, Northwich, Cheshire in Northern England. Its special virtue is that it provides an effective screen yet does not obscure completely what lies beyond it, so it can mark out a portion of the property without isolating it from the rest of the garden. It provides a transition between different parts of the garden.

Since pleaching is an activity of farmers, a busy and practical group, it should come as no surprise that it is a straightforward, undemanding process. The tools are simple, a sharp pocketknife, a pair of pruning shears, and hedge clippers. Trees most suited to pleaching are those with pliable branches. Apple, linden, hawthorn and pear trees work especially well.

Another attractive form (right), displays the fresh greenery of spring of a tunnel of pleached apple trees, trained over a support and fronted by colorful bulbs. In its more advanced form, the branches are encouraged to graft themselves to each other, so that the structure becomes self-reinforcing.

Pleaching does not only involve trees. Left is an impressive pleached hedge. Pleaching is not difficult; the main requirement is patience while the plants are in their early training stage. Few of our North American trees pleach well. It is wise to check with an experienced arborist or nursery owner before experimenting with untried species. Obviously, short-lived species, such as the willow, birch, poplar and rowan, should be avoided. Once established, maintenance involves early summer shearing as the new growth begins to harden off, and again in the fall so that the skeleton of branches will look neat during the leafless months.

The above hedge can be easily achieved. Plant your specimens four to five feet apart and train them to a single stem (see Standardizing). Keep the lower portion of the trunk free of branches selectively to encourage lateral growth. Tie jute twine in parallel lines through the plants and train the branches along the jute. After a few seasons, the branches of the adjoining plants will meet forming a continuous network of dense twigs. The jute can then be removed. Then, once the desired height and depth have been achieved, you can shear the top and sides to produce a classic, formal outline.