The weeping willow tree (Salix babylonica) is a fast-growing shade tree with a cascading, graceful canopy. This lovely deciduous tree can grow as much as 10 feet in a single year and requires adequate space to grow. The weeping willow is often found growing along the water's edge as it thrives in the moist conditions.
Weeping willows are hardy from zones 2 through 9A. They are used as a shade tree, as a specimen planting or as a screen. It is an extremely large tree, which reaches a height and spread of from 45 to 70 feet. The crown of the weeping willow is round with weeping branches--foliage is dense and fine, turning yellow in the autumn. Weeping willows adapt to most soil conditions, and can be planted in full sun to partial shade. The life of a weeping willow tree is generally 30 years--it is a fast-growing tree but has a short lifespan.
The root system of the weeping willow is very aggressive, spreading out approximately three times the distance from the trunk to the drip-line of the canopy. Roots grow on or near the surface of the soil. Site selection is very important because of this very aggressive root system. Weeping willows should not be planted near water lines, sewer lines or septic tank drain fields, which the roots could damage. Roots have been known to lift walkways and driveways.
Trunk and Branches
The wood of the weeping willow tree is weak and can suffer breakage. Since the branches of the willow naturally droop as the tree matures, it will require pruning to maintain clearance under the canopy. Pruning is needed to develop a central trunk and a strong structure. The structure should have open wide branch crotches to cut down on branch/limb breakage.
There are several cultivars available, such as: Aurea, with golden-yellow branches; Crispa, which is a corkscrew willow; Golden Curls, which has golden bark and twisting branches and leave; and the Babylon and Tristis, which are popular selections.
Pests and Disease
Common pests of the weeping willow are scales, borers, caterpillars, and aphids. There are several diseases that the weeping willow is susceptible to: root rot, crown gall, willow scab and black canker. To avoid disease, it is important to maintain a healthy tree by fertilization, watering and pruning out dead, diseased or damaged branches as soon as possible. Several fungal diseases, which cause mainly cosmetic/appearance problems, are leaf spot, powdery mildew, tar spots and rust.