Side-bells Penstemon
Penstemon secundiflorus
Side-bells Penstemon (Penstemon secundiflorus) is a Colorado-native perennial suited to the Colorado Front Range. It matures to about 20 in tall and 12 in wide, needs low to medium water, and prefers full sun. CO native perennial; supports pollinators.
Colorado nativeOn the CSU listlow to medium water20 in tall and 12 in wideXeric / water-wiseLow ignitability: OK 0-30 ft from the house, CSU score 8/10Deer-resistant
Photos
- Photo 1: "Penstemon secundiflorus - Shalana Gray 01" by Shalana Gray https://www.inaturalist.org/people/shalana is licensed under CC BY 4.0. To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0/.
- Photo 2: Craig Martin https://www.inaturalist.org/people/craigmartin
- Photo 3: Dave Powell, USDA Forest Service (retired), Wikimedia Commons (PD)
- Photo 4: "Penstemon secundiflorus - Anders Hastings 05" by Anders Hastings https://www.inaturalist.org/people/andershastings is licensed under CC BY 4.0. To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0/.
- Photo 5: "Penstemon secundiflorus bugwood" by Dave Powell, USDA Forest Service (retired) is licensed under CC BY 3.0. To view a copy of this license, visit https://creativecommons.org/licenses/by/3.0/.
- Photo 6: "20240622 Penstemon secundiflorus (Penstemon secundiflorus) [inat obs id 224438594] maybe" by schizoform is licensed under CC BY 2.0. To view a copy of this license, visit https://creativecommons.org/licenses/by/2.0/.
At a glance
Will it survive here?
- Hardiness zones
- USDA 3 to 8
- Water needs
- low to medium water
- Sun
- Best in full sun.
- 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
- 20 in tall and 12 in wide
- Planting spacing
- ~8 to 12 in apart
What it looks like, and when
- Bloom time
- late spring
- Bloom color
- pink, 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 Side-bells Penstemon good for the Colorado Front Range?
- Yes, Side-bells Penstemon is a well-suited perennial for Colorado's Front Range.
- How big does Side-bells Penstemon get?
- It matures to about 20 in tall and 12 in wide.
- How far apart do I plant Side-bells Penstemon?
- Space Side-bells Penstemon about 8 in apart for a faster, fuller bed, or up to 12 in apart for a looser planting.
- Is Side-bells Penstemon hardy on the Front Range?
- Side-bells 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 Side-bells Penstemon need?
- It needs low to medium water once established.
- Is Side-bells Penstemon native to Colorado?
- Yes. It is a Colorado native.
- Is Side-bells Penstemon deer-resistant?
- Side-bells Penstemon is generally considered deer-resistant, though no plant is deer-proof when browse pressure is high.
- Is Side-bells Penstemon a good firewise plant near the house?
- Side-bells 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 Side-bells Penstemon bloom?
- Side-bells 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.
