Populus deltoides subsp. Monilifera (P. deltoides var. occidentalis; P. sargentii)
Most Plains Cottonwood trees that carve out an existence on the Great Plains are short-lived trees. They are generally a stout, wide-branching tree, although some specimens of Plains Cottonwood can reach 80 feet in height with a trunk diameter of 3 feet. Plains Cottonwood trees are commonly found growing along the banks of the rivers and streams that flow through the Great Plains.
Initially considered a distinct tree species (Populus sargentii), it is currently considered by most botanists to be a subspecies of the Eastern Cottonwood (Poplus deltoides). Initially named Populus deltoides var. occidentalis, it now carries the moniker of Populus deltoides subsp. Monilifera.
Plains Cottonwood trees grow best on deep, rich, loamy soil. They can grow on deep, sandy soil as long as adequate irrigation is provided. The Plains Cottonwood should be planted in the full sun and can be used as a windbreak planting or a fast growing, but usually short-lived, shade tree.
The leaves of the Plains Cottonwood are somewhat triangular, ranging from 3 to 3.5 inches long and 3.5 to 4 inches wide. The green leaves are shiny and the veins may vary in color from pale to bright red. The leaf margins are coarsely rounded and the leaf stems are flattened. Fall leaf color is yellow.
The bark on young stems is greenish-tan. As the bark matures it becomes ashy-gray and develops long, deep, interconnecting furrows with broadly rounded ridges.
Leaf rust and stem cankers are the most common diseases that affect Plains Cottonwood. The premature defoliation caused by leaf rust causes a loss in growth and increases the susceptibility of the tree to more harmful disease and insect pests.
Plains Cottonwood trees are susceptible to Cytospora Canker (Cytospora chrysosperma). The presence of Cytospora Canker can result in wind damage which occurs where the canker is located.
Other diseases infecting Plains Cottonwood includes Septoria leaf spot, Alternaria leaf and stem blight, root rot, and butt rot.
Leaf feeding insect pests of Plains Cottonwood trees can cause reduced health and vigor. Common insect pests include the Cottonwood Dagger Moth (Acronicta lepusculina), Cottonwood Leaf Beetle (Chrysomela scripta), Fall Cankerworm (Alsophila pometaria), Fall Webworm (Hyphantria cunea), Forest Tent Caterpillar (Malacosoma disstria), and the Poplar Leaffolding Sawfly (Phyllocolpa bozemani).
Wood borer insects can cause severe damage or death to Plains Cottonwood trees as well as reduce the quality of lumber from the trees. The most common borers of Plains Cottonwood are the Bronze Poplar Borer (Agrilus liragus), Carpenterworm (Prionoxystus robiniae), Cottonwood Borer (Plectrodera scalator), Flatheaded Wood Borer (Dicerca divaricata), Poplar-and-Willow Borer (Cryptorhynchus lapathi), and the Poplar Borer (Saperda calcarata).
Plains Cottonwood trees are occasionally attacked by various species of aphids and mites, but the damage is not as severe as the previously mentioned insect pests.
The natural range of Plains Cottonwood extends from southern Canada south through North Dakota, South Dakota, Nebraska, Kansas, western Oklahoma, north Texas, and northeastern New Mexico. It can also be found in north Colorado, eastern Wyoming, and eastern Montana.