Identify the Cottonwoods

Salicaceae

cottonwood leaves
(Rob Atkins/Getty Images)

The common cottonwoods are three species of poplars in the section Aegiros of the genus Populus, native to North America, Europe and western Asia. They are very similar to and in the same genus as other true poplars and aspens. They also tend to rustle and chitter in a breeze.

The Eastern Cottonwood, Populus deltoides, is of the largest North American hardwood trees, although the wood is rather soft.

It is a riparian zone tree. It occurs throughout the eastern United States and just into southern Canada.

The black Cottonwood, Populus balsamifera, grows mostly west of the Rocky Mountains and is the largest Western cottonwood. It is also called Western balsam poplar and California poplar and the leaf has fine teeth unlike the other cottonwoods.

The Fremont Cottonwood, Populus fremontii occurs in California east to Utah and Arizona and south into northwest Mexico; it is similar to Eastern Cottonwood, differing mainly in the leaves having fewer, larger serrations on the leaf edge and small differences in the flower and seed pod structure.

Quick Identification Using Leaves, Bark and Flowers

Leaves: alternate, triangular, coarsely curved teeth, leafstalks flattened.
Bark: yellowish green and smooth on young trees but deeply furrowed in maturity.
Flowers: catkins, male - female on separate trees.

Quick Winter Identification Using Bark and Location

These most common cottonwoods become very large trees (up to 165 feet) and usually occupy wet riparian areas in the East or seasonally dry creek beds in the West. Mature trees have bark that is thick, grayish-brown, and deeply furrowed with scaly ridges.

Young bark is smooth and thin.