There are more than 350 types of willow trees and shrubs, most of which grow in the Northern Hemisphere. Willows are deciduous, losing their leaves in the fall. The majority of willows will grow in wet ground, and the trees usually have narrow leaves. Among the different kinds of willows are the Bebb willow, the black willow and the pussy willow.
The Bebb willow (Salix bebbian) takes its name from botanist Michael Bebb, who studied willow trees extensively in the 19th century. The Bebb willow, also called a diamond willow, grows from New England through the Great Lakes States, across most of the southern half of Canada and down into the Rocky Mountains. The Bebb willow is typically a multi-stemmed shrub or small tree, rarely growing taller than 25 feet high, according to the "National Audubon Field Guide to Trees." The Bebb willow has 1 to 3 inch long leaves that are silver-gray. The bark is maroon and in many instances, a fungus causes a diamond pattern to emerge on the trunk. The wood of the Bebb willow is a popular medium for carving items such as walking canes. The tree grows in wet soils like most willows and often exists next to streams and ponds.
The black willow (Salix nigra) can grow to 65 feet tall, but more often than not has a shrub-like demeanor with many trunks. Black willow can form dense thickets of trees from Minnesota east to New Brunswick in Canada to as far south as Georgia. Another tree that exists in wetlands, the black willow can grow in the shade but does much better when placed in the full sun. The lance-shaped leaves are from 3 to 6 inches long and usually less than 1 inch in width. Black willow has male and female flowers, called catkins in the case of willows, on separate trees. The catkins precede the leaves in the spring, making for an attractive sight. By breaking the branch off a black willow and putting it in sufficiently wet soil, you can actually start a new tree. Erosion control is an important use for the black willow, and it is the only willow with any value as a lumber species, with its wood used to make such products as boxes.
The pussy willow (Salix discolor) grows from the Northeast through the Great Lakes as far west as the Dakotas and Wyoming. The tree, which normally grows no higher than 20 feet, is also plentiful throughout most of the eastern two-thirds of Canada. Pussy willows develop a number of trunks and flourish near streams, swamps and in wet ditches. The flowers of the pussy willow emerge as early as late February in many places, long before the leaves grow in. The flowers are silver-gray catkin that resembles fur. Cut the twigs from the tree at this time of year and place them in hot water to make the flowers open up. By pruning a pussy willow back every few years, you will encourage new growth. Pussy willows tend to sucker, or sprout new trees from their own root system, making them invasive if you cease to pay attention to them.