Populus deltoides (Eastern Cottonwood) Salicaceae

One of the oldest and largest hardwood trees, the Eastern cottonwood is native to North America, growing throughout the eastern, central, and southwestern United States. It was a valuable resource as a construction material for the American Indians and European settlers who used the hard, but lightweight wood to build barns and houses. Today, cottonwood is used for pulp and sometimes for lightweight furniture.

Physical characteristics

“Trembling Leaves” 

An identifying characteristics of the Eastern cottonwood tree is that beacuase its leaves are sail-like shaped with long flat stems they have a tendency to tremble and flutter from even the slightest breeze.

Leaf: The leaf is very coarsely toothed, the teeth are curved and gland tipped, and the petiole is flat. The leaves are dark green in the summer and turn yellow in the fall. In dry locations they drop their leaves early from the combination of drought and leaf rust, leaving their fall color dull or absent. 

Flower | Seeds: Its flowers, called catkins, are produced on single-sex trees in early spring. In early summer seed capsules split open to release the numerous small seeds attached to cotton-like strands.

Trunk | Bark: The bark of a mature cottonwood is so thick that it can withstand fires with just minimum damage. Yet, they are also known for having “weak” wood and will drop branches occasionally, particularly during windy spells. 

Life span: Eastern cottonwoods typically live 70 to 100 years, but they have the potential to live 200 to 400 years if they have a good growing environment.

Ecological characteristics

In natural conditions, Eastern cottonwood trees typically grow near a water source. Cottonwood groves are typically indicitive that a water source is nearby as they consume large amounts of water in their growth cycle; a mature cottonwood tree uses 200 gallons of water a day. Cottonwoods are so dependent on water that they will drop leaves during an extended period of drought in order to conserve moisture. If a cottonwood root is cut, it will “bleed” water for days until the cut heals. 

Distribution range 

While mud banks left after floods provide ideal conditions for seedling germination, human soil cultivation has allowed them to increase their range away from such habitats. The Eastern cottonwood is native to North America, growing throughout the eastern, central, and southwestern United States, the southernmost part of eastern Canada, and northeastern Mexico. 

Importance to the ecosystem

The Eastern cottonwood is a producer, transforming the sun’s energy into food energy. Field mice, rabbits, deer, and domestic livestock eat the bark and leaves of young cottonwood trees. The tree is also used for courtship, roosting, and nesting by many different species of game birds and songbirds. It is a pioneer species, one of the first to grow on a stream bank or floodplain site, beginning a chain of ecological succession that ultimately leads to a more biodiverse steady-state ecosystem.  

Relationship with other species

Non-human: In addition to being a food source for many species, when a cottonwood loses a branch, it is likely the heartwood will begin to rot at the break, forming holes that make the ideal accommodations for birds, squirrels or bees to build nests.

Humans: American pioneers used the cottonwood’s leaves for animal fodder and herbal teas, its canopy for shelter and its wood for fire and crafts. Though cottonwood pollen aggravates allergies, these large, adaptable and hearty trees provide shade and beauty across the country. When used in home landscaping to provide cooling shade, space requirements can become an issue. As the tree matures, its roots will lift the soil surrounding the tree, referred to as root flair. 

Pests: Once past the seedling-sapling size, cottonwood trees have few significant insect or disease pests. Leaf feeding insects and leaf diseases are not uncommon, but rarely injurious.

Other interesting facts

The cottonwood is not found naturally on dry soils, but the early settlers planted it extensively around their homesteads and it has proven to be relatively drought-resistant.

Native Americans used the cottonwood to make lodge poles and to start fires. The shape of the teepee is thought to be fashioned after the shape of the cottonwood leaf.

Calling the cottonwood tree “the pioneer of the prairie”, the Kansas state legislature designated the cottonwood the official state tree of Kansas in 1937.