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 arctica Salix arctica Salix arctica, the arctic willow, is a tiny creeping willow (family Salicaceae). It is adapted to survive in Arctic conditions, specifically tundras. The arctic willow grows in tundra and rocky moorland, and is the northernmost woody plant in the world, occurring far above the tree line to the northern limit of land on the north coast of Greenland. It also occurs further south in North America on high-altitude alpine tundra, south to the Sierra Nevada in California and the Rocky Mountains in New Mexico, and in Asia to Xinjiang in China. "S. arctica" is typically a low shrub