Fast-growing trees and shrubs are grown for shade, privacy screens or windbreaks. They are useful for quick cover on bare sites where there was recent construction or for erosion control. Commercially, fast-growing trees are grown for firewood or pulpwood and fast-growing shrubs may be used to beautify highway right-of-ways and commercial landscapes.
The boxelder (Acer negundo) is a type of maple tree with compound leaves. It has a broad uneven shape when it matures at a height of 50 feet. The boxelder is fast-growing tree until maturity, which takes 10 to 20 years. It usually lives fewer than 100 years. The boxelder grows with sufficient moisture in U.S. Department of Agriculture horticultural zones 2 through 9. Boxelder easily reproduces easily from the multitude of seeds that ripen on the shrub in the fall.
The Leyland cypress (Cupressocyparis Leylandii) is a fast-growing evergreen tree in USDA horticultural zones 6 through 10. It grows in nearly all soil types and is useful as a single specimen tree, a screen or as a hedge. The Leyland cypress can even be grown in containers and kept sheared to an attractive shape. Its outstanding feature is its pyramidal shape and the way it holds its limbs all the way to the ground level. The Leyland cypress can be pruned from the bottom to form an attractive shade tree. Mature height is from 75 to 100 feet if planted in deep, moist, fertile soil. In drier areas, it will grow to about 50 feet tall.
The butterfly bush (Buddleja davidii) is a fast-growing shrub to 12 feet tall and 6 feet wide that produces colourful blooms during the growing season. For maximum bloom production, cut off the dead blooms after they fade. The butterfly bush is often pruned to within 4 inches of the ground in spring to create attractive new growth during the season and because flowers form on new wood. It grows in average soil in USDA horticultural zones 5 through 10.
Silverthorn (Elaeagnus pungens) is a fast-growing sprawling shrub to 15 feet tall and 10 feet wide with long cane-like stems and attractive silvery foliage. It produces fragrant cream-coloured flowers in the spring and numerous 1-inch red fruit in the fall attractive to wildlife. It responds well to severe pruning and can be used as a hedge or tall screen. It has thornlike growths that are actually young stems that grow rapidly. Elaeagnus is appropriate for planting in USDA horticultural zones 7 through 9.