Rocky Mountain Penstemon
Penstemon strictus
Rocky Mountain Penstemon (Penstemon strictus) is a Colorado-native perennial suited to the Colorado Front Range. It matures to about 30 in tall and 24 in wide, needs low to medium water, and prefers full sun to partial shade. CO native perennial; supports pollinators.
Colorado nativeOn the CSU listlow to medium water30 in tall and 24 in wideXeric / water-wiseLow ignitability: OK 0-30 ft from the house, CSU score 8/10Deer-resistant
Photos
- Photo 1: (c) Stephen Hornbeck, some rights reserved (CC BY)
- Photo 2: JerryFriedman, Wikimedia Commons (CC-BY-SA)
- Photo 3: peganum from Henfield, England, Wikimedia Commons (CC-BY-SA)
- Photo 4: JerryFriedman, Wikimedia Commons (CC-BY-SA)
- Photo 5: (c) gwynmwilliams, some rights reserved (CC BY)
- Photo 6: (c) gwynmwilliams, some rights reserved (CC BY)
At a glance
Will it survive here?
- Hardiness zones
- USDA 3 to 8
- Water needs
- low to medium water
- Sun
- Best in full sun; tolerates partial shade.
- Soil
- clay, loam, sandy
- Soil pH
- 6.5 to 8.0
- Hail tolerance
- high
- Wind tolerance
- high
- Salt tolerance
- moderate
- Site uses
- Slopes & erosion control
How big, what shape?
- Mature size
- 30 in tall and 24 in wide
- Planting spacing
- ~17 to 24 in apart
What it looks like, and when
- Bloom time
- late spring, early summer
- Bloom color
- blue, purple
- Bloom length
- Long (several weeks)
- Foliage
- Deciduous
Who else benefits
- Pollinator value
- high
- Deer
- Generally deer-resistant
- Colorado native
- Yes
- Native ecoregion
- shortgrass prairie, foothills
Also worth knowing
- Fire rating
- Low ignitability: OK 0-30 ft from the house, CSU score 8/10
Planting & establishment
Native perennial; deep-water first season to establish, then minimal water needed.
Frequently asked questions
- Is Rocky Mountain Penstemon good for the Colorado Front Range?
- Yes, Rocky Mountain Penstemon is a well-suited perennial for Colorado's Front Range.
- How big does Rocky Mountain Penstemon get?
- It matures to about 30 in tall and 24 in wide.
- How far apart do I plant Rocky Mountain Penstemon?
- Space Rocky Mountain Penstemon about 17 in apart for a faster, fuller bed, or up to 24 in apart for a looser planting.
- Is Rocky Mountain Penstemon hardy on the Front Range?
- Rocky Mountain Penstemon is hardy in USDA 3 to 8. The Colorado Front Range spans roughly USDA 4b to 6a, so it is well within range.
- How much water does Rocky Mountain Penstemon need?
- It needs low to medium water once established.
- Is Rocky Mountain Penstemon native to Colorado?
- Yes. It is a Colorado native.
- Is Rocky Mountain Penstemon deer-resistant?
- Rocky Mountain Penstemon is generally considered deer-resistant, though no plant is deer-proof when browse pressure is high.
- Is Rocky Mountain Penstemon a good firewise plant near the house?
- Rocky Mountain Penstemon is rated 8 of 10 in CSU Extension Fact Sheet 6.305 (2025), where higher means less ignitable, so it can go within 0 to 5 feet of the house as well as out to 30 feet when kept watered and tidy. 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.
- How long does Rocky Mountain Penstemon bloom?
- Rocky Mountain Penstemon blooms for several weeks, a long-season performer on the Front Range. Bloom timing shifts a week or two with elevation and spring weather.
