Living Willow Hedges, or 'fedges' = fence + hedge. Willows, sallows, and osiers form the genus Salix (Latin for willow), which consist of around 400 species of deciduous trees and shrubs. Willow are native to moist soils in cold and temperate regions of the Northern Hemisphere. Almost all willows take root very readily from cuttings. Young, thin willow cuttings are known as withies, longer willow rods are known as whips.