The genus salix, better known by the common name willow, are members of the salicacea family. These deciduous shrubs and trees thrive when planted near water and are commonly spotted along riverbanks, ponds and in swamp lands. Most salix trees are easily recognized for their elegant, long, thin leaves and rounded drooping branches. More than 400 varieties of salix trees and shrubs are found growing throughout the Northern Hemisphere.
Found in the eastern United States and parts of Canada and Mexico, the salix nigra is known as the black willow. Trees may reach heights of 100 feet and have multiple trunks with many branches attached to each trunk. The slender, glossy-green leaves of the black willow are narrow, shaped like a shield and are about 3 to 5 inches long. The salix nigra produces a yellow flower called a catkin. Fruit on the salix nigra is in a small capsule, is red-brown in color and contains small, fuzzy green seeds. Salix nigra thrives in sunny areas and prefers moist soil conditions. The black willow is a good food source for deer, rabbits, beaver and rodents. Bees and butterflies consume the nectar, and leaves are eaten by moths, butterflies and caterpillars.
The hardy salix babylonica is commonly called the babylon weeping willow. Trees are short-trunked and have a wide, spreading crown and long, drooping branches. Salix babylonica trees can reach heights of 50 feet and thrive in areas of full sun and in moist soil. Leaves are silvery-olive green, narrow and slender and are about 3 to 6 inches long. Flowers of the salix babylonica are yellow and bloom in April or May. The salix babylonica grows well in USDA zones 4 through 9. Salix babylonica willows are not ideal for small areas and are most often found along shorelines of rivers, lakes and streams. The root system of the babylon weeping willow is extremely invasive and may clog sewer lines and water pipes. Butterflies, moths and caterpillars are attracted to the salix babylonica and will eat the leaves and consume the sap.
The fast-growing salix alba, more commonly known as the white willow, is found growing in most USDA zones throughout the country. The salix alba is a large tree, often reaching heights of 75 to 100 feet. The crown is rounded and branches droop and are low to the ground. Foliage is 2 to 4 inches long, narrow and is a medium shade of green. The flower of the white willow is a catkin, sometimes yellow or white in color. The fruit is brown, unattractive and contains the green seeds of the tree. White willows thrive in full sun and moist soil conditions. Trees are often found near sources of water such as ponds, rivers and streams. Salix alba is susceptible to insects, aphids, leaf beetles and powdery mildew.
Considered to be a shrub or a small tree, the salix pentandra is commonly known as the laurel willow or the bay-leaved willow. One of the smallest varieties of willow, the salix pentandra reaches a height of 30 to 45 feet and has a compact, oval form. The Salix pentandra is hardy through USDA zone 5 and is not frost tender. Leaves are a dark, lustrous green and are 1 to 2 inches long. The salix pentandra produces a yellow flower in May and a fruit-like seed that ripens in June. When dried or bruised, the leaves of the salix pentandra are sweetly aromatic and are often used in potpourri. Salix pentandra willows thrive in areas of full sun, in soils that are moist and are most often found along streams, marshes or in wet woodlands.