Size of Seedless Cottonwood Trees

Hopi Indians used cottonwood for carving.

Cottonwood trees are infamous for the abundance of feathery, silken seeds they produce each year. The seeds make a mess on the ground around the tree and throughout the yard as the windblown "cotton" scatters everywhere. Seedless cottonwood trees (Populus deltoides) are a better choice for homeowners that want a large, fast-growing tree without the litter. Seedless cottonwoods are always male trees and are often called "cottonless" cottonwoods. Siouxland and Robusta are widely available male seedless cottonwood trees. Seedless cottonwoods grow fast and die young.

Tree Size

Seedless cottonwood trees grow from 36 to 190 feet tall, depending upon growing conditions, cultivar and placement. While cottonwoods may grow as fast as 36 inches in a single season, it can still take 35 years for the tree to reach maximum height. The trees only live about 85 years. At maturity, the trunk can be as slender as 10.7 inches in diameter to more than 6 feet thick. The seedless cottonwood Robusta has a narrower, more vase-shaped habit than Siouxland cottonwood, which features a broader, spreading canopy. The trees have dense branch systems.

Foliage

Glossy, dark, leathery-looking green on top and lighter, matte green on the undersides, seedless cottonwood foliage grows into a dense canopy that provides deep, cooling shade in summer. The large leaves are deltoid to oval-like triangles with broadly rounded angles and measure from 3 to 5 inches long and wide. Buds can be up to 3/4 inch long. The leaf margins are widely serrated, with larger teeth at the leaf base than at the pointed tip. Seedless cottonwood trees can produce thick canopies that spread as wide as 75 feet. The leaves turn yellow in the fall.

Root System

The long, thick roots of seedless cottonwood trees can spread out widely in search of water. Roots grow from 100 to nearly 200 inches deep and thrust outward beyond the dripline as far as necessary to reach moisture. The roots may invade water lines and damage building foundations if planted too close.

Structural Problems

While seedless cottonwood's extensive root system helps hold the tree in place during floods, the aboveground parts of the tree are structurally brittle. Ice and snow accumulation can snap branches, and high winds can break the limbs or knock down the whole tree. Wood harvested from seedless cottonwood trees is too lightweight, soft and difficult to season for it to be of much use to the homeowner.

References

• USDA Forest Service: Fact Sheet - Eastern Cottonwood
• USDA Forest Service: Populus Deltoides - Botanical and Ecological Characteristics
• USDA Forest Service: Populus Deltoides
• Urban Forest Ecosystems Institute: SelecTree - Eastern Cottonwood
• Learn 2 Grow: Populus Deltoides "Siouxland"
• North Dakota State University; Cottonwood; Dale E. Herman, et al.

Resources

• Floridata; Populus Deltoides; Steve Christman; January 2011