Salix viminalis is a multistemmed shrub growing to between 3 and 6 m (9.8 and 19.7 ft) (rarely to 10 m (33 ft)) tall. It has long, erect, straight branches with greenish-grey bark. The leaves long and slender, 10–25 cm long but only 0.5–2 cm broad; they are dark green above, with a silky grey-haired underside. The flowers are catkins, produced in early spring before the leaves; they are dioecious, with male and female catkins on separate plants. The male catkins are yellow and oval-shaped; the female catkins are longer and more cylindrical; they mature in early summer when the fruit capsules split open to release the numerous minute seeds.