Willows are common ornamental trees around the world. Most willows do best with a lot of water, but some can be drought tolerant. Plant your willows with adequate space around them to accommodate their size. Don't plant willows near septic tanks, sewers or other underground plumbing. Their roots can be aggressive and can damage underground infrastructure. Willows grow best in USDA Hardiness Zones 5 through 8.
Black willows are multiple-trunked trees that can range from shrub size to more than 100 feet in high. In their natural range, black willows generally grow along streams or marshes in places where they can get full sun. If you are growing black willows in your yard, they grow best in constantly moist, well-draining soil. Water your tree when the top 1/4 to 1/2 inch of soil feels dry to the touch. Plant your black willows where they can grow in full sun.
The contorted willow is native to China and the Korean Peninsula. On the smaller side, these trees grow to 20 to 30 feet. Contorted willows have a corkscrew shape to their branches and limbs that is easier to see after the leaves have fallen. The contorted willow grows best in full sun and with moist soil, but it is more drought tolerant than most willows. This particular type of willow was introduced to the United States in 1923 when Arnold Arboretum received a cutting from China.
Weeping willows are a common, very large ornamental tree. Weeping willows can easily reach 45 feet in height, and can sometimes reach 75 feet. Although the weeping willow does best in full sun, it can also do well in partial sun. The weeping willow grows naturally near bodies of water, and as such has high water requirements. It grows in a variety of soils, as long as the soils drain well. Weeping willows are defined by their long branches that extend from the central trunk and arch over toward the outside of the tree. In some cases, if left unpruned, these branches can touch the ground.