The willows have numerous hybrids and comprise of around 300 species deciduous trees and shrubs that are scattered in both hemispheres of the globe. They are found in the Arctic area to South Africa and even southern Chile. The white willow has an interesting characteristic. Of about 70 of the North American species of the white willow, about 30 grow as trees measuring up to 80 feet, in some other places across the globe they may only grow up to five or seven feet and remain just as shrubs. The white willow bears alternating, lanceolate, pockmarked leaves that are ash-gray in color and glossy on either side. Another interesting aspect of the white willow is the fact that different trees of the species bear male and female flowers that emerge in catkins on leafy stems simultaneously with the leaves. Indigenous to European countries, white willow is now found abundantly in North America as well as in Asia. The tree best thrives in humid areas like riverbanks and can be grown from partially matured cuttings during the summer or from hardwood cuttings during the winter. Normally, the white willow trees are often pollarded, and the bark of the tree is shredded during spring from branches of trees that are two to five years old.
Salix species / Wilg - Kruidwis - Google Sites, https://sites.google.com/site/kruidwis/kruiden-a/salix-species-wilg (accessed January 19, 2017).