Identify the Cottonwoods

cottonwood leaves

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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 name comes from the fact that their seeds are produced from a fluffy white cotton-looking covering.

The trees like wet conditions and relatively hardy, even in areas that see temporary flooding. Their lowest branches may not be reachable, and if they are not surrounded by other trees or buildings they are often spread out as wide as they are tall.

Types

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

The Fremont Cottonwood, also known as the Western Cottonwood or the Rio Grande Cottonwood, Populus fremontii, occurs in California east to Utah and Arizona and south into northwest Mexico. Named after 19th century American explorer John C. Fremont, it is similar to the 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.

ID Using Leaves, Bark and Flowers

  • Leaves: Alternate, triangular, coarsely curved teeth, leafstalks flattened. Black Cottonwood leaves may also have an ovate shape and the leaves of mature trees may show a light rust color on the side facing the ground.
  • Bark: Yellowish-green and smooth on young trees but deeply furrowed in maturity.
  • Flowers: Catkins, male-female on separate trees. On the Eastern Cottonwoods, males produce reddish catkins, while females produce yellowish-green catkins.. Black Cottonwoods produce yellow catkins on both male and female trees, while both genders of Western Cottonwoods produce red catkins.
  • Fruits: Eastern Cottonwoods produce green capsule-looking fruits containing multiple cottony seeds. The fruits of Black Cottonwoods are similar except they have a hairy appearance. The Freemont Cottonwood's fruit differs in that it is light brown and egg-shaped. It bursts into three to four sections to release its seeds.

Winter ID 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.

Branches are usually thick and long. Since the wood is weak, branches routinely break off, and foliage is uneven.

Uses

Cottonwood is used to make storage boxes and crates, paper, matchsticks, and plywood. It is easy to carve, making it popular with artisans as well. Herbalists also use the buds and bark of cottonwood to treat aches and pains, skin health and other uses.