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 caprea the height at which the graft is made. Plants can also be grown from greenwood cuttings, which make attractive creeping mounds. Hardwood cuttings are often difficult to root. Both tannin and salicin can be extracted from goat willow bark. The tree is not considered a good source of timber, as its wood is both brittle and known to crackle violently if burned. As with the closely related "Salix discolor" (American pussy willow), it is also often grown for cut flowers. See Pussy willow for further cultural information, which apply to both species. In Scandinavia it has been fairly common to