A tree attaining a height of 80 ft in Japan, and a girth of 12 ft or more; bark shallowly fissured; winter growth-buds oblong, closely appressed to the shoot, the catkin-buds broadly ovoid; young growths densely downy. Leaves lanceolate to narrowly elliptic or oblong, usually finely tapered at the apex, to about 4 in. long and 1⁄2 in. wide, silky on both sides when young, almost glabrous when mature, dark green above, paler, often bluish beneath, finely toothed; petioles to about 3⁄16 in. long. Stipules small, toothed, ovate or rhombic, slightly oblique. Catkins appearing with the leaves on short leafy stalks; scales truncate, hairy at the base. Male catkins 1 in. or slightly more long. Stamens two, with rather stout filaments. Female catkins to about 13⁄4 in. long, their scales persistent in the fruiting stage. Ovary silky, sessile; style very short; stigmas entire.
Native of Japan in Hokkaido and N. Honshu, known there as ‘Shiro-yanagi’ (white willow). It is one of a group of closely related species in N.E. Asia which have been regarded as the counterparts in that region of the western S. fragilis and S. alba, but their affinity is rather with S. matsudana.
S. koreensis Anderss. (1868) ?S. pierotii Miq. (1867) – Allied to S. jessoensis, but the young growths and leaves more glabrous, the petioles longer, and the style longer, with bifid stigmas. Native of continental N.E. Asia and S. Japan.
S. pierotii Miq. was described from two specimens collected in the Japanese island of Kyushu, one by Pierot and the other by Siebold. The female specimen appears to have been S. koreensis, but the flowers of the male specimen were described, with a query, as having a single stamen and, unless defective, must have belonged to a different species.