About two hundred species of trees and shrubs belong to the salix genus, often difficult to recognize from each other, given the ease with which they hybridize with each other. The white willow is a deciduous tree, fast growing, but not very long-lived, which reaches 15-20 meters in height, with a trunk with a maximum diameter of 50-60 cm; it originates from southern and central Europe, northern Africa and Asia. It has enlarged crown, with branches often arched and hanging; the bark is dark gray, with deep cracks; the leaves are silver-gray, long and thin, with a light down on the lower page. In March the flowers appear, at the same time as the leaves, the male ones are yellowish catkins, the female ones are smaller and greenish. In June the fruits ripen, seed capsules that are scattered by the wind with a white hair called pappus.
The salix alba trees, in general, love sunny positions, but develop without problems even in partial shade. They do not like mountainous terrain, preferring the plains and coasts. The white willow it does not tolerate harsh climates, preferring the temperate Mediterranean climate.
This tree is usually grown up to 1200 meters in height, as at higher altitudes the rigid temperatures compromise its health; this genus of plants, in fact, tolerates temperatures down to -2 ° C without particular suffering.