Mat penstemon
Penstemon caespitosus
Mat penstemon (Penstemon caespitosus) is a Colorado-native groundcover suited to the Colorado Front Range. It matures to about 2 to 4 in tall and 8 to 15 in wide, needs low water, and prefers full sun. Native mat-forming penstemon with intense blue-purple blooms. Needs sharp drainage.
Colorado nativelow water2 to 4 in tall and 8 to 15 in wideXeric / water-wisePlant Select®Low ignitability: OK 0-30 ft from the house, CSU score 8/10Deer-resistant
Photos
- Photo 1: no rights reserved
- Photo 2: (c) Andrey Zharkikh, some rights reserved (CC BY)
- Photo 3: no rights reserved
At a glance
Will it survive here?
- Hardiness zones
- USDA 3 to 8
- Water needs
- low water
- Sun
- Best in full sun.
- Soil
- sandy, well drained only
- Soil pH
- 6.5 to 8.5
- Hail tolerance
- high
- Wind tolerance
- high
- Salt tolerance
- low
- Site uses
- Slopes & erosion control
How big, what shape?
- Mature size
- 2 to 4 in tall and 8 to 15 in wide
- Growth habit
- Mat-forming
- Planting spacing
- ~10 to 15 in apart
What it looks like, and when
- Bloom time
- late spring, early summer
- Bloom color
- blue, purple
- Bloom length
- 2 to 3 weeks
- Foliage
- Semi-evergreen
- Winter cover
- Partial winter cover
What it will do to your yard
- Foot traffic
- No foot traffic
- Lawn alternative
- No-mow lawn alternative
Who else benefits
- Pollinator value
- high
- Deer
- Generally deer-resistant
- Colorado native
- Yes
- Native ecoregion
- foothills, montane
Also worth knowing
- Fire rating
- Low ignitability: OK 0-30 ft from the house, CSU score 8/10
Using Mat penstemon as a groundcover
Mat penstemon forms a low mat. It fills in to a moderately dense cover. On a slope it helps knit the soil together and control erosion.
Planting & establishment
Drainage is critical, wet feet kill it. Minimal water once established.
Frequently asked questions
- Is Mat penstemon good for the Colorado Front Range?
- Yes, Mat penstemon is a well-suited groundcover for Colorado's Front Range.
- How big does Mat penstemon get?
- It matures to about 2 to 4 in tall and 8 to 15 in wide.
- How far apart do I plant Mat penstemon?
- Space Mat penstemon about 10 in apart for a faster, fuller cover, or up to 15 in apart for a looser planting.
- Is Mat penstemon hardy on the Front Range?
- Mat 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 Mat penstemon need?
- It needs low water once established.
- Is Mat penstemon native to Colorado?
- Yes. It is a Colorado native.
- Is Mat penstemon deer-resistant?
- Mat penstemon is generally considered deer-resistant, though no plant is deer-proof when browse pressure is high.
- Is Mat penstemon a good firewise plant near the house?
- Mat 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.
- Is Mat penstemon a Plant Select® winner?
- Yes. Mat penstemon is in Plant Select®, the plant-recommendation program run by Colorado State University and Denver Botanic Gardens to highlight plants that thrive in the region.
- Can you walk on Mat penstemon?
- Mat penstemon isn't meant for foot traffic, site it where you won't need to walk across it.
- Can Mat penstemon replace a lawn?
- Yes, Mat penstemon works as a no-mow lawn alternative on the Front Range. Expect a season or two of weeding and watering while it fills in before it reads as a lawn replacement.
- Will Mat penstemon spread or stay put?
- Mat penstemon is mat-forming. Give it room to fill in and edit the edges to keep it where you want it.
- Does Mat penstemon stay green in winter?
- Mat penstemon keeps partial cover through Front Range winters.
- Is Mat penstemon good for a slope?
- Yes. Mat penstemon helps hold soil on Front Range slopes and control erosion once its roots knit in.
- How long does Mat penstemon bloom?
- Mat penstemon blooms for about two to three weeks on the Front Range. Bloom timing shifts a week or two with elevation and spring weather.
