The willows gave the world its first painkiller, and they give the early garden its first stir of life. Long before much else has woken, Salix push out silvery catkins that the season's first bees work over on a warm afternoon. The bark carries salicin, the compound Greek and Native American healers steeped for fever and ache and the ancestor of aspirin, so a willow is a medicine chest as much as a tree.

Most gardeners picture a willow standing knee deep in water, and many here do love a wet foot, but the genus keeps a few surprises. Salix tristis is a dwarf gray shrub of dry ground; Salix integra 'Hakuro Nishiki' leafs out dappled pink and cream. Cut a stem, push the cutting into damp soil, and a willow will usually root, the oldest party trick in the family and the reason a single tree can furnish a hedge.