Populus tremuloides, commonly called quaking aspen, is perhaps most noted for its beautiful white bark, its deep green foliage that quakes in the slightest breeze and its golden yellow fall foliage color. It has the widest geographical distribution of any North American tree, being indigenous to Alaska and most of Canada, the Pacific Northwest, New England, the Great Lakes and south in the Rockies to New Mexico and Arizona. It is a medium sized deciduous tree that typically grows 20-50’ tall with a narrow, rounded crown. Ovate-triangular to nearly round, dark glossy green leaves (to 3” long) are finely toothed. Leaves flutter in even the smallest amount of wind due to flattened leaf stalks. Leaves turn a beautiful golden yellow in fall. Aspens are dicecious, with male and female flowers appearing in separate catkins on separate clones in spring (April in St. Louis) before the foliage.