Many different hybrid poplars exist, the most common of which are hybrids of the cottonwood (Populus deltoides) and the black poplar (P. nigra). Hybrid poplars have very similar features and tend to be fast growers, gaining 5 to 8 feet in height each year. Hybrid poplars grow 40 to 60 feet tall and 20 to 35 feet wide at maturity and can thrive in many different climates and soil compositions. Although many propagated hybrid poplars are males and produce no flowers or seeds, the females will produce light-brown seeds that appear in masses of cotton-like pod formations.
Identify hybrid poplar leaves by color. Hybrid poplar leaves are medium to dark-green, or sometimes silver-green, and turn yellow in the fall.
Look at the leaf shape to identify hybrid poplar leaves. The hybrid poplar's leaves are simple, meaning that they aren't divided into smaller leaflets on the stem, and are triangular in shape.
Study the leaves' arrangement on the branches to identify hybrid poplar leaves. The hybrid poplar has alternately-arranged leaves, meaning that the leaves grow from buds that are not directly across from one another on the branches, but in a staggered fashion.
Look at the leaf margins, or edges. Hybrid poplar leaves have coarse "teeth" around the margins, instead of smooth edges.