Pleaching or plashing was common in gardens from the late Middle Ages until the 18th century. This technique is a kind of weaving of the branches of deciduous trees or shrubs to form a living fence. Sometimes branches woven together grow together, a natural grafting known as inosculation. Sir Walter Scott brought the technique back to popularity in England when he described such a fence in The Fortunes of Nigel.
"Espalier is a horticultural technique of pruning and grafting used together to train trees to create two-dimensional forms with the branches. This technique was originally developed during the Middle Ages as a way to grow fruit trees within castle walls, without taking up space needed for other activities, and to add decoration to the walls."