Rocky Mountain Douglas fir
Pseudotsuga menziesii var. glauca
Rocky Mountain Douglas fir (Pseudotsuga menziesii var. glauca) is a Colorado-native tree suited to the Colorado Front Range, rated "Recommended" on the 2024 Front Range Tree Recommendation List. It matures to about 40 to 80 ft tall and 15 to 25 ft wide, slow-growing, needs medium water, and prefers full sun to partial shade.
Colorado nativemedium water40 to 80 ft tall and 15 to 25 ft wideDeer-resistant
Photos
- Photo 1: (c) J Straka, some rights reserved (CC BY)
- Photo 2: (c) Norma Piedra, some rights reserved (CC BY)
- Photo 3: (c) Caleb Catto, some rights reserved (CC BY)
At a glance
Will it survive here?
- Hardiness zones
- USDA 4 to 6
- Water needs
- medium water
- Sun
- Best in full sun; tolerates partial shade.
- Soil
- loam, sandy, well drained only
- Soil pH
- 6.0 to 8.2
- Hail tolerance
- high
- Wind tolerance
- high
- Salt tolerance
- moderate
How big, what shape?
- Mature size
- 40 to 80 ft tall and 15 to 25 ft wide
- Mature form
- Pyramidal
- Spacing / clearance
- ~25 ft of clearance
- Growth rate
- Slow
- Lifespan
- Long-lived
What it looks like, and when
- Foliage
- Evergreen
Who else benefits
- Pollinator value
- low
- Deer
- Generally deer-resistant
- Colorado native
- Yes
- Native ecoregion
- foothills, montane
Also worth knowing
- Fire rating
- Ignitable (CSU): keep 30+ ft from the house, thinned
Site factors to consider
- Critical: Cold HardinessThe average low suits it fine; our real cold risk is the swings, late frosts, and intense winter sun, so wrap young trunks and give it shelter.
Frequently asked questions
- Is Rocky Mountain Douglas fir good for the Colorado Front Range?
- Yes, Rocky Mountain Douglas fir is a well-suited tree for Colorado's Front Range, rated "Recommended" on the 2024 Front Range Tree Recommendation List.
- How big does Rocky Mountain Douglas fir get?
- It matures to about 40 to 80 ft tall and 15 to 25 ft wide.
- How much room does Rocky Mountain Douglas fir need?
- Give Rocky Mountain Douglas fir about 25 ft of clearance from buildings, fences, and other trees so the mature canopy isn't crowded.
- What shape does Rocky Mountain Douglas fir grow into?
- Rocky Mountain Douglas fir typically grows into a pyramidal, conical outline that is widest at the base. This is the species' usual mature form, named cultivars (columnar, weeping, or compact selections) can differ, so check the specific cultivar.
- Is Rocky Mountain Douglas fir hardy on the Front Range?
- Rocky Mountain Douglas fir is hardy in USDA 4 to 6. The Colorado Front Range spans roughly USDA 4b to 6a, so it is well within range. That said, it carries a cold-hardiness caution: The average low suits it fine; our real cold risk is the swings, late frosts, and intense winter sun, so wrap young trunks and give it shelter.
- How much water does Rocky Mountain Douglas fir need?
- It needs medium water once established.
- How fast does Rocky Mountain Douglas fir grow?
- Rocky Mountain Douglas fir is a slow-growing tree. Growth rate depends on water and site conditions on the Front Range.
- How long does Rocky Mountain Douglas fir live?
- Rocky Mountain Douglas fir is long-lived, a multi-generational tree given good siting and care. Actual lifespan varies with site, water, and care.
- Is Rocky Mountain Douglas fir native to Colorado?
- Yes. It is a Colorado native.
- Is Rocky Mountain Douglas fir deer-resistant?
- Rocky Mountain Douglas fir is generally considered deer-resistant, though no plant is deer-proof when browse pressure is high.
- Is Rocky Mountain Douglas fir a good firewise plant near the house?
- Rocky Mountain Douglas fir is an evergreen conifer, and CSU Extension notes conifers tend to be ignitable because of their oil and pitch, even when well watered, so keep it 30 or more feet from the house and keep it thinned and well maintained. This is general guidance based on CSU Extension Fact Sheet 6.305 (2025), 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.
