Rocky Mountain Maple
Acer glabrum
Rocky Mountain Maple (Acer glabrum) is a Colorado-native tree suited to the Colorado Front Range, rated "Recommended for Most Sites" on the 2024 Front Range Tree Recommendation List. It matures to about 10–25 ft tall and 10–20 ft wide, slow-growing, needs medium to high water, and prefers full sun to partial shade. Best in cooler, part-shade spots, not hot dry exposure.
Colorado nativemedium to high water10–25 ft tall and 10–20 ft wideXeric / water-wiseZones 1–3 (can be planted near the house)
Photos
- Photo 1: (c) CK2AZ, some rights reserved (CC BY)
- Photo 2: (c) Rich Sommer, some rights reserved (CC BY), uploaded by Rich Sommer
- Photo 3: (c) Caleb Catto, some rights reserved (CC BY), uploaded by Caleb Catto
At a glance
Will it survive here?
- Hardiness zones
- USDA 4–8
- Water needs
- medium to high water
- Sun
- Best in full sun; tolerates partial shade.
- Soil
- clay, loam, sandy
- Soil pH
- 6.0–8.2
- Hail tolerance
- moderate
- Wind tolerance
- moderate
- Salt tolerance
- moderate
- Firewise (defensible space)
- Zones 1–3 (can be planted near the house)
How big, what shape?
- Mature size
- 10–25 ft tall and 10–20 ft wide
- Mature form
- Rounded
- Spacing / clearance
- ~20 ft of clearance
- Growth rate
- Slow
- Lifespan
- Medium
What it looks like, and when
- Fall color
- Orange, red, yellow
- Foliage
- Deciduous
Who else benefits
- Pollinator value
- high
- Deer
- Not deer-resistant
- Colorado native
- Yes
- Native ecoregion
- foothills, montane
Site factors to consider
- Critical: Insects & DiseasesMain pressure here is Aphids and honeydew, so keep it vigorous with steady water and a well-chosen site.
Common problems on the Front Range
- Aphids and honeydew
- Verticillium wilt on some species
- Leaf scorch in hot, dry, windy sites
These are general tendencies for this group of plants on the Front Range, not a diagnosis. Many are stress-driven and preventable with good siting and watering. For a specific plant or an active problem, consult a certified arborist or your local CSU Extension office.
Planting & establishment
Deep water every 2–4 weeks during establishment (first 1–2 growing seasons), then water sparingly per CSU PlantTalk.
Frequently asked questions
- Is Rocky Mountain Maple good for the Colorado Front Range?
- Yes, Rocky Mountain Maple is a well-suited tree for Colorado's Front Range, rated "Recommended for Most Sites" on the 2024 Front Range Tree Recommendation List.
- How big does Rocky Mountain Maple get?
- It matures to about 10–25 ft tall and 10–20 ft wide.
- How much room does Rocky Mountain Maple need?
- Give Rocky Mountain Maple about 20 ft of clearance from buildings, fences, and other trees so the mature canopy isn't crowded.
- What shape does Rocky Mountain Maple grow into?
- Rocky Mountain Maple typically grows into a broad, rounded crown, the classic shade-tree silhouette. This is the species' usual mature form, named cultivars (columnar, weeping, or compact selections) can differ, so check the specific cultivar.
- Is Rocky Mountain Maple hardy on the Front Range?
- Rocky Mountain Maple is hardy in USDA 4–8. The Colorado Front Range spans roughly USDA 4b–6a, so it is well within range.
- How much water does Rocky Mountain Maple need?
- It needs medium to high water once established.
- How fast does Rocky Mountain Maple grow?
- Rocky Mountain Maple is a slow-growing tree. Growth rate depends on water and site conditions on the Front Range.
- How long does Rocky Mountain Maple live?
- Rocky Mountain Maple has a moderate lifespan for a Front Range tree. Actual lifespan varies with site, water, and care.
- What color does Rocky Mountain Maple turn in fall?
- Rocky Mountain Maple turns orange, red, and yellow in autumn. Fall color intensity varies with the season and site on the Front Range.
- Is Rocky Mountain Maple native to Colorado?
- Yes. It is a Colorado native.
- Is Rocky Mountain Maple deer-resistant?
- No. Rocky Mountain Maple is not considered deer-resistant and may need protection where deer browse.
- Is Rocky Mountain Maple a good firewise plant near the house?
- Rocky Mountain Maple is a lower-fuel choice suitable in defensible-space zones 1–3, it can be planted near the house when kept well irrigated and maintained. This is general suitability guidance based on CSU Extension firewise plant lists, not a guarantee that any plant won't burn, a well-irrigated, well-maintained plant is the goal. Follow CSU Extension defensible-space guidance and check with your local fire district before planting in the wildland-urban interface.
- Is Rocky Mountain Maple prone to pests or disease on the Front Range?
- Rocky Mountain Maple can be affected by aphids and honeydew and other issues common to this group on the Front Range. These are general tendencies, not a diagnosis, many are stress-driven and preventable with good siting and watering. For a specific plant or an active problem, consult a certified arborist or CSU Extension.
