Rocky Mountain Maple

Acer glabrum

Sapindaceae

• Keystone plant
• Spokane Native
• Sun-Part Shade
• 15’-30' tall x 15' wide
• Drought Tolerant: Moderate
• Flower Color: yellowish-green (April - May)
• Wildlife Value: Seeds eaten by grosbeaks and small mammals; foliage browsed by deer and elk; hosts Imperial moth caterpillars

Rocky Mountain Maple is a native deciduous small tree or large shrub that typically grows 15-30 feet tall with a 15-foot spread, though it can occasionally reach 40 feet. It thrives in moist, well-drained soils in full sun to partial shade, making it an excellent understory plant. While it prefers moderate moisture, once established it adapts to various conditions including drought, poor soils, and strong winds. It grows naturally along streams, wooded slopes, and forest edges throughout the Spokane region.

The tree displays three-lobed (occasionally five-lobed) leaves that are bright green through summer, turning brilliant yellow to reddish-orange in fall. Small, fragrant yellowish-green flowers appear in spring alongside new foliage, followed by reddish samaras (winged seeds) that add visual interest. The smooth gray bark and reddish young twigs provide winter appeal. Often multi-stemmed, it can be grown as a shrub or trained to a small tree form.

As a keystone native species, Rocky Mountain Maple provides crucial wildlife habitat and food. Seeds are consumed by grosbeaks, small mammals, and birds, while flowers and seeds support various wildlife throughout the seasons. The foliage is browsed by deer, elk, cattle, and sheep. Indigenous peoples historically used the wood for snowshoe frames. The plant serves as a larval host for the Imperial moth.

Rocky Mountain Maple excels as a specimen tree, in mixed borders, and for slope stabilization. It's approved for Spokane's street tree program under power lines (Class I) and works beautifully in woodland gardens and naturalized plantings. Excellent companions include Ponderosa Pine, Oregon Grape, Mock Orange, Douglas-fir, and native wildflowers. The tree's compact size makes it ideal for residential yards, providing multi-season interest with spring flowers, summer foliage, and outstanding fall color.