The poplar tree family is a large group of trees that include the white poplar, cottonwood tree and quaking aspen. Poplars are typically short lived, though their rapid growth rate makes them a common shade tree selection. Trees are weak-wooded and susceptible to damage by a wide range of environmental and insect pest sources.
Types of Poplar Trees
Poplar trees and their relatives belong to the genus Populus, a collection of over 150 species and subspecies. Native American species include the quaking aspen, which grows in every part of Canada and the United States except the Southeast, and is known for the green-and-white leaves which seem to shimmer under the lightest breeze. Eastern and swamp cottonwood are two common East Coast species, named for the furry white seeds and leathery leaves with hairy white undersides. White poplar is a species introduced from Europe and Asia in the 1700s, grown for shade and its ornamental leaves.
White Poplar Growth Habit
White poplar (Populus alba) is a soft-wooded, deciduous tree which usually grows to between 50 and 75 feet, but sometimes as tall as 100 feet. While specimens can be trained to a single trunk, poplars frequently grow as a multi-stemmed tree in naturalized settings. Due to its suckering tendencies, in which the tree sends up young clone shoots along the roots at some distance from the parent tree, poplar can be somewhat weedy or invasive.
Flower and Leaf Description
Trees are dioecious, occurring as separate male and female individuals and bearing small, inconspicuous flowers on long catkins in the spring before leaves emerge. Leaves are similar in shape to maple leaves, star-shaped with 3 to 5 deeply divided lobes. In color, leaves are a dark shiny green above and fuzzy white below. Leaves begin falling from the tree in mid-summer, though the leaves remaining by autumn turn an undistinguished yellow.
Bark and Branch Description
As implied by its name, the bark along the trunk of this species of poplar is a dingy white in color, though new twigs, branches and shoots are a silvery gray. Trees require pruning to develop a strong, single-trunked, upright form; however, even with careful pruning, the brittle wood of the white poplar makes the tree rather vulnerable to breakage by high winds and ice.
Care and Culture
White poplar performs best when grown in full sun, in soils ranging from well-drained, rich loams to poor clay soils. Trees are relatively indifferent to soil alkalinity or acidity. Avoid planting trees along sidewalk medians or roads, as the strong roots are notorious for lifting pavement and concrete.