Willow are very cross-compatible, and numerous hybrids occur, both naturally and in cultivation. A well-known ornamental example is the weeping willow ("Salix × sepulcralis"), which is a hybrid of Peking willow ("Salix babylonica") from China and white willow ("Salix alba") from Europe. The hybrid cultivar 'Boydii' has gained the Royal Horticultural Society's Award of Garden Merit. Numerous cultivars of "Salix" L. have been developed and named over the centuries. New selections of cultivars with superior technical and ornamental characteristics have been chosen deliberately and applied to various purposes. Most recently, "Salix" has become an important source for bioenergy production and for
Salix matsudana this character is variable in many willows (e.g. crack willow "Salix fragilis" can have either one or two), so even this difference may not be a meaningful species distinction. Chinese willow has been introduced into many areas as an ornamental tree, including Australia, Europe and North America. A particularly popular cultivar of this species is "Salix matsudana" 'Tortuosa', the "Corkscrew willow" (also known as the Hankow willow, curly willow, dragon's claw, or globe willow), in which the branches and twigs grow in a spiral, twisting manner. As a result of the ornamental shape of the branches and twigs, this cultivar