Salix babylonica a gold-yellow in autumn. The flowers are arranged in catkins produced early in the spring; it is dioecious, with the male and female catkins on separate trees. "Salix babylonica" was described and named scientifically by Carolus Linnaeus in 1736, who knew the species as the pendulous-branched ("weeping") variant then recently introduced into the Clifford garden in Hartekamp in The Netherlands. Early Chinese cultivar selections include the original weeping willow, "Salix babylonica" 'Pendula', in which the branches and twigs are strongly pendulous, which was presumably spread along ancient trade routes. These distinctive trees were subsequently introduced into England from Aleppo in
Salix babylonica northern Syria in 1730. These plants are all females, readily propagated vegetatively, and capable of hybridizing with various other kinds of willows, but not breeding true from seed. This type of tree is grown very easily through plant propagation. Two cultivated hybrids between pendulous "Salix babylonica" and other species of "Salix" willows also have pendulous branchlets, and are more commonly planted than "S. babylonica" itself: Cultivars derived from either of these hybrids are generally better adapted than "S. babylonica" to the more humid climates of most heavily populated regions of Europe and North America. A similar willow species also native