quaking aspen (Populus tremuloides)

Species info:

Leaves: Simple, thin, and broadly ovate; 1½–3 inches long and wide; finely serrated margins. Leaves are attached by long, flattened petioles (1–2½ inches), which cause them to “tremble” or flutter in the slightest breeze.

Leaflets: N/A (simple leaves)

Leaf Surface: Glossy green above and lighter beneath.

Bark: Green-white to cream-colored, smooth on younger trees; develops furrows and dark patches with age.

Flowers: Inconspicuous catkins; rarely produce viable seed in the western U.S., as most reproduction occurs vegetatively through root suckers.

Botanical: Populus tremuloides

Family: Salicaceae

Mature Height: 20–50 feet in landscapes; can reach 70 feet in native mountain settings.

Canopy Spread: 15–25 feet

Foliage Type: Deciduous

Tree Shape: Upright with narrow crown when young; broadens with age.

Flowers: Inconspicuous

Fruit: Inconspicuous

Fall Color: Brilliant yellow, occasionally tinged with orange or red; highly variable by elevation and soil conditions.

Water Use: Moderate to high; prefers moist, well-drained, tilled areas.

Hardiness: Zones 1–6; tolerates a wide range of cold climates.

Soil Preference: Best in neutral to slightly acidic, well-drained soils; avoid compacted or dry urban sites.

Wildlife Value: Provides food and cover for a wide variety of birds and mammals; important as a pioneer species in forest regeneration.

Pests/Pathogens: Numerous pests and pathogens including oyster shell scale, leaf miners, aphids, leafrollers, stem cankers, and leaf spot diseases. Regular leaf cleanup in fall is recommended to reduce disease recurrence.

Notable Traits: Iconic Colorado native valued for its striking fall color and white bark; regenerates readily from root suckers forming colonies.

Colorado Suitability: Performs best in groves rather than single plantings; thrives in higher elevations and cool mountain climates; often short-lived and disease-prone in urban or low-elevation settings; best planted in protected sites away from lawns and irrigation competition.

Planting recommendation: Conditionally recommended; more suitable for elevations +7800’. ‘Prairie Gold’ reported to do better at lower elevations.

Information Sources:

• Michael Kuhns, Trees of Utah and the Intermountain West (Utah State University Press, 1998)

• Michael Dirr, Manual of Woody Landscape Plants (University of Georgia, 1990)

• D. Leatherman, H. McNulty, M. Schomaker, and D. Lynch, Aspen: A Guide to Common Problems in Colorado, Colorado State Forest Service (CSU, 1986)