Acer glabrum Torr.
Rocky Mountain Maple
Aceraceae (Maple Family)
USDA Symbol: ACGL
Rocky Mountain maple is a multi-stemmed, 10-30 ft. tree or shrub with a 10-15 ft. spread. Though inconspicuous, the early spring flowers of this maple are quite fragrant. Its shiny, green, deciduous leaves turn yellow to reddish-orange in fall. Smooth, gray bark; red twigs; and reddish, winged seeds provide winter interest. The northernmost maple in the New World, it extends through southeastern Alaska. The Latin species name, meaning "hairless," refers to the leaves.
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Plant CharacteristicsDuration: Perennial
Leaf Retention: Deciduous
Leaf Arrangement: Opposite
Leaf Complexity: Simple
Leaf Margin: Lobed , Serrate
Fruit Type: Samara
Size Notes: Up to about 30 feet tall, with slender spreading branches.
Leaf: Green above with lighter veins, slightly paler below.
Bloom InformationBloom Color: Yellow , Green
Bloom Time: Apr , May
Bloom Notes: Usually monoecious, in small clusters.
DistributionUSA: AK , AZ , CA , CO , ID , MT , NE , NM , NV , OR , SD , UT , WA , WY
Native Distribution: Mts. of western U.S.
Native Habitat: Wooded hills; ravines along streams; above 4500 ft.
Growing ConditionsWater Use: Low
Light Requirement: Sun
CaCO3 Tolerance: Medium
Soil Description: Moist, well-drained, rocky soils.
Conditions Comments: Though not as handsome as vine maple, this species is more cold hardy. Rocky Mountain maple does not tolerate heat and its leaves may scorch if grown in open, hot, dry and windy sites.
BenefitUse Wildlife: Deer, elk, cattle, and sheep browse the foliage.
Interesting Foliage: yes
PropagationDescription: Can be propagated from seeds sown soon after harvest.
Seed Collection: As soon as samaras turn yellowish or reddish brown and the seeds inside are firm, filled out, and dark brown. Best to gather from the tree as seeds that have already dropped lose viability quickly and are easily infested. Seed is usually not extracted from the samara. Keep in cold, moist storage.
Seed Treatment: Best results from seeds are obtained by alternating warm & cold stratification.
Commercially Avail: yes
Find Seed or Plants
Find seed sources for this species at the Native Seed Network.
View propagation protocol from Native Plants Network.
National Wetland Indicator Status
From the National Organizations DirectoryAccording to the species list provided by Affiliate Organizations, this plant is on display at the following locations:
Native Seed Network - Corvallis, OR
Web ReferenceWebref 30 - Calflora (2018) Calflora
Webref 23 - Southwest Environmental Information Network (2009) SEINet - Arizona Chapter
Additional resourcesUSDA: Find Acer glabrum in USDA Plants
FNA: Find Acer glabrum in the Flora of North America (if available)
Google: Search Google for Acer glabrum
MetadataRecord Modified: 2023-05-31
Research By: TWC Staff