All willows, including the graceful weeping willow (Salix spp.), are members of the Salicaceae family of plants. With over 90 different types of willows, this group of deciduous trees and shrubs grow to varying sizes and shapes, fulfilling an assortment of roles and functions in the landscape and environment. Although weeping willows grow well in many North American landscapes, this tree is not a native variety.
Size and Shape
Like many types of willows, weeping willows grow rapidly in optimal conditions. Weeping willows grow to a mature height and width of near 45 feet, although some may reach 70 feet, creating a spherical shape in the landscape. The pendulous, drooping branches provide a dense circle of shade beneath the canopy. Other types of willows, such as the Pacific willow (Salix lucida), retain a more conical, upright appearance, reaching a mature height and width of 50 by 30 feet. Dwarf Arctic willows (Salix purpurea) are shrubs that reach only 3 to 6 feet at maturity.
Willows can survive in various types of climates, depending on the specific plant. Weeping willows grow in U.S. Department of Agriculture (USDA) plant hardiness zones 2 through 9a, while Peking willows (Salix matsudana) grow in USDA zones 5 through 10, and Pacific willows grow in USDA zones 3 through 9.
Most varieties of willows grow best in full sunlight. While some smaller shrub willows grow well in mass plantings as hedges and borders, weeping willows prefer open areas that provide an abundance of light, although they can grow in very light shade. Heavy shade and poor air circulation can hinder healthy growth, and may increase the risk of disease.
Although some willows may grow naturally with minimal help, weeping willows require regular pruning during early growth to promote strong structure. This type of tree can suffer from poor collar formation, a condition that weakens the crotch and increases the risk of breakage. Depending on the location, mature trees also may require frequent pruning to allow for pedestrian clearance below the canopy. All willows can experience leaf and branch shedding, a type of littering around the trunks that can lead to the growth of bacteria and fungus. Removing this vegetative debris helps eliminate this potential source of illness.