They have very deep taproots which enable the tree to absorb large amounts of water even if its above-ground water supply is low. The female catkins grow in hanging clusters and are covered in soft, cottony hairs. The black cottonwood bears large pointed buds covered with scales. These buds are filled with a sticky resin that resembles strawberry jam. It is this resin that gives off a strong balsam odor.
Cottonwoods grow rapidly and stumps and fresh-cut twigs with sprout readily.
Habitat and Geographical Range Black cottonwoods are found in riparian habitats along the North Pacific coast and on the western side of the Rocky Mountains, it also extends down into southern California and Nevada. Its range extends east to about southwestern Alberta. It is often found in pure stands or mixed with willows and red alder. It can be found below 5000 ft. It can be found on silty, gravelly or sandy soils.