Like its cousin, Fremont Cottonwood, Narrowleaf Cottonwood is a very large tree, which, in pure stands sometimes forms a closed leafy canopy high above the ground. This tree tends to grow at higher elevations and is more common north of Arizona in the foothills of the Rocky Mountains. In Arizona, these trees are found along the upper reaches of the creeks draining the Mogollon Rim: Sycamore, Wet Beaver, and East and West Clear creeks. Interestingly there is a disjunct population in the Santa Catalina Mts. along Bear Canyon. Flowers, both male and female, are very similar to Fremont Cottonwood.