White Willow is a medium-sized/large deciduous tree growing up to 10–30 m tall. The leaves are paler than most other willows, due to a covering of very fine, silky white hairs, in particular on the underside. An attractive, native tree that prefers moist, deep, rich soils and boggy sites. The yellow male and green female catkins appear on separate trees in April. Bees are attracted to the flowers, and a range of butterfly and moth larvae, including the Large Tortoiseshell and Comma butterfly, feed on the leaves. This tree contains phenolglycosides, salicortin and salicin. The latter is an analgesic which led to the formulation of aspirin. The bark is often macerated in ethanol to produce a tincture.