It is a deciduous shrub or small tree, reaching a height of 8–10 m (26–33 ft), rarely to 13 m. The leaves are 3-12 cm long and from 2-8 cm wide, broader than most other willows. The flowers are soft silky, and silvery 3-7-cm-long catkins are produced in early spring before the new leaves appear; the male and female catkins are on different plants (dioecious). The male catkins mature yellow at pollen release, the female catkins mature pale green. The fruit is a small capsule 5-10 mm long containing numerous minute seeds embedded in fine, cottony hairs. The seeds are very small (about 0.2 mm) with the fine hairs aiding dispersal; they require bare soil to germinate.
- S. c. var. caprea – lowland regions throughout the range, leaves thinly hairy above, densely hairy below, 5-12 cm long, stipules persistent until autumn
- S. c. var. sphacelata (Sm.) Wahlenb. (syn. S. caprea var. coaetanea Hartm.; S. coaetanea (Hartm.) Floderus) – high altitudes in the mountains of central and northern Europe (Alps, Carpathians, Scotland, Scandinavia), leaves densely silky-hairy on both sides, 3-7 cm long, stipules early deciduous
The scientific name, and the common name goat willow, probably derive from the first known illustration of the species in Hieronymus Bock‘s 1546 Herbal, where the plant is shown being browsed by a goat. The species was historically also widely used as a browse for goats, to which Bock’s illustration may refer