It is a medium-sized deciduous tree, growing to heights of up to 15–30 m (49–98 ft) (rarely more), with a trunk up to 2 m (6.6 ft) in diameter and a broad, rounded crown. The bark is smooth and greenish-white to greyish-white with characteristic diamond-shaped dark marks on young trees, becoming blackish and fissured at the base of old trees. The young shoots are covered with whitish-grey down, including the small buds. The leaves are 4–15 cm (1+1⁄2–6 in) long, five-lobed, with a thick covering of white scurfy down on both sides, but thicker underneath; this layer wears off 8 cm (3+1⁄4 in) long, produced in early spring; they are dioecious, with male and female catkins on separate trees; the male catkins are grey with conspicuous dark red stamens, the female catkins are greyish-green. The female catkins lengthen to 8–10 cm (3+1⁄4–4 in) after pollination, with several green seed capsules, maturing in late spring to early summer. It also propagates by means of root suckers growing from the lateral roots, often as far as 20–30 m (65–100 ft) from the trunk, to form extensive clonal colonies.