Answer: Not Pleaching.

The Normandy hedgerows were made up of linear mounds or walls of earth topped by a thick tangle of trees and brush. Most of the hedgerows dated back hundreds of years, some back to the time of William the Conqueror. Centuries of soil compaction and vegetation growth meant the hedgerows were dense, sturdy obstacles that were virtually impossible to penetrate. On a flat and otherwise featureless coastal plain the hedgerows created heavily dissected terrain with limited line of sight and restricted virtually all off-road movement.