Swallow-tailed Willow Salix alba

The white willow is a medium to large size, fast-growing, deciduous tree that has a weeping or rounded habit and can reach a height of 50 to 70 feet. In the spring, this plant has male and female flowering catkins that appear on separate trees. The male catkins are up to 2 inches long and have tiny yellow flowers. The female catkin is smaller with greenish flowers. The lanceolate leaves are medium to dark green on the upper surface and silky white underneath. The bark is yellowish-brown. This tree is a member of the Salix or willow family. 

White willow is a native of Europe, North Africa, and Central Asia. It was brought to the United States in the 1700s and has become naturalized. This weeping tree is found growing along stream banks, lakeshores, floodplains, wetlands, or other wet sites. 

The genus name, Salix, is the Latin name for this tree. The species name, alba, means white. The common name, white willow, references the white hairs that color the undersides of the leaves.  

White willow thrives in moisture-rich soil and full sun to partial shade. It is tolerant of most moist, well-drained soil types, but it is intolerant to dry soils. Pruning may be done in the late winter or early spring. The wood is weak and brittle, and it is easily damaged by wind, snow, or ice. The tree also litters the grounds with leaves, twigs, and branches that require clean-up.

White willow can be propagated by softwood cuttings in early summer or hardwood cuttings during the winter. Small mammals like to feed on the leaves and catkins while songbirds use the twigs for nesting. Insects pollinate the flowers.

White willow may be used in the landscape but is not recommended as a street tree. It creates excessive litter, and the roots system can disturb drainage systems or concrete. It is best used in larger landscapes along streams, ponds, or excessively wet areas. The cultivars are available with a weeping habit or showy colored twigs for added winter interest.

Seasons of Interest:

Bloom: Spring,    Foliage:  Spring, Summer, and Fall

Quick ID Hints:

• weeping or rounded habit
• yellowish-brown bark, yellowish-green stems
• narrow, lanceolate medium to dark green leaves with white silky undersides, and serrate margins
• fall leaf color is pale yellow to yellow
• male catkins and female catkins are on separate trees
• male catkins, up to 2 inches long with tiny yellow flowers
• female catkin, smaller, and tiny greenish flowers

Insects, Diseases, and Other Plant Problems:  White willow can attract aphids, flea beetles, sawfly larvae, willow scale, borers, lace bugs, and caterpillars. It is susceptible to anthracnose, rust diseases, crown gall, root rot, honey fungus, powdery mildew, leaf spots, cankers, and blights. This tree has very shallow roots that can pose a problem in residential areas because of interference with drainage systems. 

VIDEO created by Grant L. Thompson for “Trees, Shrubs, and Woody Vines for Landscaping” a plant identification course offered by the Department of Horticulture at Iowa State University.