Pleaching

Pleaching or plashing is a technique of interweaving living and dead branches through a hedge for stock control. Trees are planted in lines, the branches are woven together to strengthen and fill any weak spots until the hedge thickens. Branches in close contact may grow together, due to a natural phenomenon called inosculation, a natural graft. Pleach also means weaving of thin, whippy stems of trees to form a basketry effect.

Pleaching or plashing (an early synonym) was common in gardens from late medieval times to the early eighteenth century, to create shaded paths, or to create a living fence out of trees or shrubs. This craft had been developed by European farmers who used it to make their hedge rows more secure.Julius Caesar (circa 60 B.C.) states that the Gallic tribe of Nervii used plashing to create defensive barriers against cavalry.

In hedge laying, this technique can be used to improve or renew a quickset hedge to form a thick, impenetrable barrier suitable for enclosing animals. It keeps the lower parts of a hedge thick and dense, and was traditionally done every few years. The stems of hedging plants are slashed through to the centre or more, then bent over and interwoven. The plants rapidly regrow, forming a dense barrier along its entire length.

In garden design, the same technique has produced elaborate structures, neatly shaded walks and allées. This was not much seen in the American colonies, where a labor-intensive aesthetic has not been a feature of gardening: "Because of the time needed in caring for pleached allées," Donald Wyman noted, "they are but infrequently seen in American gardens, but are frequently observed in Europe."

After the second quarter of the eighteenth century, the technique withdrew to the kitchen garden, and the word dropped out of English usage, until Sir Walter Scott reintroduced it for local colour, in The Fortunes of Nigel (1822). After the middle of the nineteenth century, English landowners were once again planting avenues, often shading the sweeping curves of a drive, but sometimes straight allées of pleached limes, as Rowland Egerton's at Arley Hall, Cheshire, which survive in splendidly controlled form.

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