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 glauca Salix glauca Salix glauca is a species of flowering plant in the willow family known by the common names gray willow, gray-leaf willow, white willow, and glaucous willow. It is native to North America, where it occurs throughout much of Alaska, northern and western Canada, and the contiguous United States south through the Rocky Mountains to northern New Mexico. It can also be found in Greenland, northwestern Europe, and Siberia. This willow is usually a shrub growing up to tall, but in appropriate habitat it becomes a tree up to tall. The smooth gray bark becomes furrowed with age. The