Narrowleaf Cottonwood

About Narrowleaf Cottonwood in Alberta

Narrowleaf cottonwood is a native southern Alberta riparian cottonwood of dynamic river corridors, especially the Oldman, St. Mary, Waterton, and related river systems. For ARA, it is important as a range-edge native tree, a floodplain and river-history species, and a hybrid-complex cottonwood that must be documented carefully before a pure-species identification is assumed.

Identification: Leaves are narrow, willow-like, lanceolate to narrowly ovate, generally about 4 to 9 cm long, with finely crenate-serrate to serrate margins. Petioles are short and round rather than strongly flattened. Intermediate leaf width, coarser teeth, or longer petioles should raise hybrid caution.

Alberta range and habitat: Narrowleaf cottonwood is native in southern Alberta and reaches its northern range limit in the province. It is particularly associated with the Oldman, St. Mary, and Waterton Rivers, with other possible or candidate southern river sites requiring careful verification.