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 fragilis frequently with the type. It is a smaller shrubby tree, rarely exceeding tall, with completely hairless leaves up to 9 cm long and 2–3 cm broad. According to some botanists, it is a distinct species (treated as "Salix decipiens" Hoffm.), with, in this view, "S. fragilis" then being a hybrid between "S. decipiens" and "S. alba". Some other botanists regard "S. decipiens" as itself being a hybrid between "S. fragilis" and "S. triandra". Little evidence supports either of these suggestions. It readily forms natural hybrids with white willow "S. alba" in Europe and Asia, the hybrid being named "Salix" ×