Poplar , Cottonwood
Fast-growing, tough trees. Grown primarily and especially appreciated in interior regions with hot summers and cold winters. Don’t do as well in mild-winter areas and in coastal climates where temperature fluctuation is minimal. Trees have aggressive surface roots that crowd out other plants, heave pavement, and clog sewer and drainage lines; best suited to rural areas and fringes of large properties.Most poplars will sucker if their roots are cut or disturbed. They are subject to many pests and diseases. Despite their liabilities, some of these trees are beautiful or distinctive enough to be widely old. Many have good fall color. Leaves of most are roughly triangular, sometimes toothed or lobed. Pendulous catkins (denser on male trees) appear in spring before leafout. Female trees later bear masses of cottony seeds that blow about and become a nuisance; for that reason, male (seedless) varieties are the best choice and are usually offered in nurseries.Populus alba
Native to Europe, Asia. To 40–70 ft. high and wide. Common name refers to woolly white leaf undersides and to light-colored young bark. Leaves are 2–5 in. long, usually with three to five lobes. A –lively– tree with leaves that move even in light breezes, showing flickering white and green highlights. Poor fall color. Tolerates wide range of soils. Suckers profusely–an advantage if it is planted as a windbreak, otherwise a problem.Populus angustifolia
Native from Alberta toMexico, primarily in RockyMountains; grows at elevationsto 8,000 ft. To 50–60 ft. talland 35–45 ft. wide, with finelytoothed, narrow, willowlikegreen leaves to 5 in. long.Young bark is green.Populus fremontii
Native to Californiaand central Rockies south toMexico. To 40–60 ft. or taller,30 ft. wide. Glossy yellow-green, coarsely toothed, virtually triangular leaves turn bright lemon yellow in fall. Leaves persist almost all winter in Zone 12. ‘Nevada’ is a male variety.Populus tremuloides
Native throughout mountains of the West, at elevations to 9,000 ft. Generally performs poorly or grows slowly in lowlands; usually short lived in warmer climates. To 20–60 ft. tall, 15–30 ft.wide; often grows as a multitrunked tree or in a clump. Smooth, pale gray-green to whitish bark. Dainty, roundish, 2–4-in., glossy green leaves clutter with the slightest movement of air. Brilliant golden yellow fall color. Good background tree for native shrubs and wildflowers. Apt to suffer from sudden dieback or borers.