salix

Salix is a genus of about 400 to 500 species of deciduous trees and shrubs in the family Salicaceae, commonly known as willows or sallows. They are widespread in cool temperate regions of the Northern Hemisphere and parts of South America, typically growing along rivers, wetlands, and other damp sites.

Willows vary from low shrubs to large trees. They usually have simple, alternate leaves that are often long and lanceolate with finely serrated margins. Many species flower in early spring with catkins; most willows are dioecious, producing male and female plants, though some species bear both kinds of flowers on the same plant. The bark is often smooth when young and becomes fissured with age. Wood is generally soft and light, and many species root readily from cuttings or broken branches.

Ecology and habitat requirements: willows are highly adapted to moist soils and flood-prone environments. They stabilize riverbanks and provide habitat for a wide range of organisms. Willows can spread vegetatively through root suckers and coppice readily, enabling rapid recovery after disturbance.

Uses and significance: willows have long been used ornamentally in landscapes and for stabilizing banks. Willow bark contains salicin, a chemical related to salicylic acid, historically used in medicine. Wood is used for wicker, light carpentry, and turnery. Some species are employed in phytoremediation and as bioenergy crops.

Notable species include Salix alba (white willow), Salix nigra (black willow), Salix fragilis (crack willow), and Salix matsudana (Japanese willow). There are numerous hybrids and cultivars, including ornamental weeping forms.