Salix babylonica but beyond China, it has not generally been as successfully cultivated as some of its hybrid derivatives, being sensitive to late-spring frosts. In the more humid climates of much of Europe and eastern North America, it is susceptible to a canker disease, willow anthracnose ("Marssonina salicicola"), which makes infected trees very short-lived and unsightly. "Salix babylonica" (Babylon willow) has many cultivars, including: Various cultivars of "Salix matsudana" (Chinese willow) are now often included within "Salix babylonica", treated more broadly, including: Yet other weeping willow cultivars are derived from interspecific "Salix" hybrids, including "S. babylonica" in their parentage. The most widely
Salix nigra Salix nigra Salix nigra, the black willow, is a species of willow native to eastern North America, from New Brunswick and southern Ontario west to Minnesota, and south to northern Florida and Texas. It is a medium-sized deciduous tree, the largest North American species of willow, growing to tall, exceptionally up to , with a trunk diameter. The bark is dark brown to blackish, becoming fissured in older trees, and frequently forking near the base. The shoots are slender and variable in color from green to brown, yellow or purplish; they are (like the related European "Salix fragilis") brittle at