Salix alba aka White Willow

Salix alba, or white willow, is a large deciduous tree. It belongs to the willow family, Salicaceae. Its native range spans Europe to northern China and northwest Africa. It is also native to Britain and Ireland. People brought it to North America, where it has spread. It grows beside streams, lakes, floodplains, and other wet ground. In Connecticut, it can escape gardens and invade nearby land.

This fast-growing tree needs room for its broad crown. Garden trees reach about 50–70 feet [15.2–21.3 metres] tall. Other accounts give heights of 82–100 feet [25–30.5 metres]. Low branches form a rounded crown, sometimes with drooping growth. The trunk may fork close to the ground. Bark ranges from yellow-brown to dark grey, with deep grooves. Slender, flexible twigs range from yellow to yellow-brown. Narrow, pointed leaves have toothed edges and grow in an alternate pattern. Their green tops contrast with pale, silky hairs beneath. These hairs give the crown a light, silvery look. Leaves turn yellow or bronze-yellow and fall late.

Catkins open in spring, with March–April bloom reported in Chicago. Male and female flowers grow on separate trees. Male catkins bear small yellow flowers and stand out more. Female flowers are green and less easy to see. Insects carry pollen between the flowers. The fruit forms a capsule that holds many seeds. It adds little to the tree's garden value. Small mammals eat the leaves and catkins. Songbirds use the twigs to build their nests.

White willow grows best in full sun and moist or wet soil. It also accepts some shade, but does not tolerate dry ground. It grows in sand, loam, clay, and chalk. It accepts acid, neutral, and alkaline soils, including poorly drained sites. The RHS rates its cold hardiness as H6. Chicago lists USDA zones 3–7; UConn reports survival in zone 2. Large wet landscapes suit it better than streets or small gardens. Growers can raise new trees from stem cuttings. People have used its wood for crates, pallets, baskets, and carving. Historical uses include tree extracts for pain, fever, and gout.

Its weak wood breaks under wind, ice, or snow. Fallen leaves, twigs, and limbs need frequent cleanup. Shallow roots can disrupt drains and concrete. The tree also forms suckers and has a short life. Aphids, beetles, sawflies, scale, borers, and caterpillars may attack it. Diseases include canker, rust, anthracnose, mildew, blight, and root rot.