Overview
Populus angustifolia is a fast-growing deciduous tree of western North American stream sides, reaching 40–60 feet (12–18 m) tall with a narrow, conical to rounded crown and a trunk 1–1.5 feet (30–45 cm) in diameter. Unlike the broad leaves of most cottonwoods, its leaves are narrow and lance-shaped, 2–4 inches (5–10 cm) long, finely toothed, glossy green above and paler beneath, resembling those of a willow. The species is dioecious, with separate male and female trees bearing drooping catkins in early spring before the leaves; female trees release tufted, cotton-like seeds in late spring. The smooth yellow-green bark of young trees furrows and grays with age. P. angustifolia grows along mountain streams, rivers, and moist canyon bottoms from Canada through the Rocky Mountains to Mexico, mostly between 5,000 and 8,000 feet (1,500–2,400 m). It grows quickly but is short-lived, has brittle wood that breaks in storms, and suckers from the roots to form thickets.
Native Range
Populus angustifolia is native to western North America, from Alberta and Saskatchewan south through the Rocky Mountains to Arizona, New Mexico, and northern Mexico. It grows along mountain streams, rivers, and moist canyon bottoms, mostly between 5,000 and 8,000 feet (1,500–2,400 m).Suggested Uses
Used for streambank stabilization, riparian restoration, windbreaks, and quick shade on large moist sites. Spaced 20–30 feet (6–9 m) apart, it suits parks, farmland edges, and naturalized waterways rather than confined yards.How to Identify
Appearance
Size & Dimensions
Height40' - 60'
Width/Spread20' - 35'
Reaches mature size in approximately 20 years
Bloom Information
As a wind-pollinated tree, P. angustifolia produces no showy flowers. Male and female catkins hang from separate trees in early spring, March to April, before the leaves expand. Female catkins ripen into capsules that release tufted, cotton-like seeds in late spring.
Detailed Descriptions
Flower Description
greenish to reddish catkinsFoliage Description
glossy greenGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Grow P. angustifolia in full sun in moist to wet soil along streams, ponds, or low ground. It tolerates seasonal flooding, gravelly riverbanks, and a range of soil textures and roots deeply where water is near the surface. Soil pH from 6.0 to 8.0 is suitable. The tree grows rapidly but is short-lived, and its brittle wood and root suckers make it suited to open riparian sites rather than small gardens. It is hardy in USDA zones 3 through 7. Young trees need steady moisture to establish.Pruning
Prune in late summer or autumn, when cottonwoods are least prone to disease and heavy sap flow. Remove dead, broken, or crossing branches and any low suckers from the base. Heavy cutting prompts weak, fast watersprout regrowth.Pruning Schedule
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