Enter your ZIP to see whether this is legal to plant in your state, and whether it survives your winter.
Rocky Mountain penstemon is rated fire resistant, with favorable scores and regional guidance that retains important qualifications.
Penstemon strictus receives an eight-out-of-ten score from Idaho Firewise. The joint Colorado State University Extension and Colorado State Forest Service publication repeats that score, within its recommended interval for defensible-space Zones 1 and 2. Colorado credits Idaho materials, so the repeated number should not be counted as two unrelated trials.
Nevada's forestry and extension guide assigns low fire hazard. This is a rough estimate, expressly distinguished from scientific trials. The guide also warns that browning plants often become hazardous and advises mowing grasses and forbs as browning starts.
New Mexico's FireWise table adds elevation guidance for this perennial. It says yes at 5,000 through 8,000 feet, while leaving the 4,000-foot and 9,000-plus categories unknown or doubtful. Together, the favorable scores and regional recommendations support the fire-resistant rating, with Nevada's vegetation-care warning and New Mexico's elevation guidance accompanying their respective findings.
Form
perennial
Mature height
~2 ft
Water need
low
Rated in
Colorado / Rocky Mountain Front Range; Lake Tahoe Basin, Nevada and California; New Mexico; southern Idaho / Intermountain
On this lot
1. Fire evidence and conditions
Fire evidence
Fire-resistant — location does not change the cited classification.
Colorado State University Extension and the Colorado State Forest Service publish Fact Sheet 6.305 for Colorado's WUI and varied ecosystems. FireApproved exposes all 114 exact source owners at Colorado publication scope while retaining score, elevation, water, and Idaho-carrier lineage. Publication scope is not suitability for every Colorado site or zone.
Southern Idaho (ID footprint); partial normalized coverage · 2013-11-08
The official database labels itself "For Southern Idaho" and describes Idaho residents at the urban-rangeland interface. FireApproved publishes 419 existing plant owners that cite its scored rows. This bounded Southern Idaho scope is regional context, not statewide coverage or a conclusion that the score transfers unchanged to every Idaho site.
New Mexico Forestry Division publishes this as its FireWise Plant List for New Mexico. FireApproved accounts for all 140 printed rows and publishes 95 exact same-rank owners already represented in the directory; 29 exact taxa without an existing record, 14 unresolved spellings or higher-rank matches, one compound taxon cell, and one species row whose only apparent owner has an infraspecific printed identity remain held. Every published row retains the source's Y, N, ?, or blank elevation cells. Publication scope does not erase those elevation limits or establish suitability for every New Mexico site.
Nevada Division of Forestry and University of Nevada Cooperative Extension publish Bulletin 06-01 for the Lake Tahoe Basin and vicinity. FireApproved publishes 83 exact rated owners as basin context across Nevada and California. Rough estimates are not statewide or site ratings.
2. Why this plant is relevant here
State distribution
Documented in AZ, CA, CO, ID, NM, UT, WY.
Native range
Current cited native range in AZ, CO, NM, UT, WY.
Introduced / established
2 sourced range or established records. This is not an invasive warning.
USDA hardiness
Documented minimum 3b; no upper limit is documented.
3. Legal, ecological, and broader status
Legal-list status
Seed-list status
Reported invasive here
Broader regional context
Federal context
How to read this page
The status above is computed from the cited rows below: independent recommendations can support a fire-resistant result, an avoid row can produce keep-away, and disagreement stays visible as conflict. Placement notes preserve each source’s own scheme rather than translating unlike rules into one scale. This is evidence about a plant, not permission to plant it in every part of the defensible space; Zone 0 remains noncombustible.
Native and introduced range evidence
These are exact U.S. botanical-area records from the cited range source. Native and
introduced describe biogeographic relationship, not fire performance or planting approval.
Doubtful and extinct rows stay visible but do not count as current presence.
The lossless worldwide derivative is retained once in the research corpus; object pages repeat only exact U.S. areas needed by the local lens. The JSON twin carries the same page assertions.
Plant hardiness evidence
These values describe the plant source. Your ZIP zone comes from the separate 2023 USDA
Plant Hardiness Zone Map. Whole-zone values stay whole-zone, and a single unresolved value
is not treated as a tolerance range. Different source boundaries stay separate: overlapping
statements are compared independently, while only ranges with no shared zone are called a conflict.
Source location: PlantCharacteristics record 52295, Temperature, Minimum (°F).
Where its sources say to plant it
Placement rules below use each source's own distances or named zones, tied to its rating.
They are not interchangeable with the directory's current Zone 0 guidance.
Fire Resistance of Plants Master Database: plantable at 30' from home [Idaho minimum planting distance] (with its recommendation)
Ignition-Resistant Landscape Plants: suitable for defensible-space zones 1-2 (score 8+) [CSU defensible-space zone] (with its recommendation)
Home Landscaping Guide for Lake Tahoe and Vicinity: Fire Hazard column: low [tahoe-guide-2006] (with its recommendation)
FireWise Plant List for New Mexico: PDF page 6, Flowers and Ground Covers, p6-r14 [nm-emnrd-firewise-table-row] (with its recommendation)
The evidence
Grouped by what each source concluded. Primary evidence rated the plant itself
(a lab, field program, or original curation); corroboration compiled or
republished another source's rating and resolves to its root lineage.
“fire-resistance score 8 of 10”
· score 8 (idaho-0-10)
Ignition-Resistant Landscape Plants (Fact Sheet 6.305) — Colorado State University Extension / Colorado State Forest Service (Wildfire Mitigation Series) · 2025 · original sourcePrimary evidenceField programlineage: idaho-tree resolves to Fire Resistance of Plants Master Database
“ignitability score 8 of 10”
· score 8 (idaho-0-10)
CSU 6.305 table lists Penstemon strictus (Rocky Mountain penstemon) with the preserved ignitability score.
Table 1's Fire Hazard column prints “low” for this taxon. The guide calls the rating a rough estimate of potential flammability, not a result of scientific trials. Its footnote says plants that turn brown often become high fire hazards and tells readers to mow grasses and forbs when they begin to turn brown.
FireWise Plant List for New Mexico — New Mexico Energy, Minerals and Natural Resources Department, Forestry Division · 2003 Forestry Division PDF · original sourceCorroborationCompilationlineage: csu-nmsu-firewise
“FireWise Plant List for New Mexico”
Listed as Penstemon strictus (Purple mountain penstemon) in Flowers and Ground Covers. Printed elevation cells: 4,000 ft=?, 5,000 ft=Y, 6,000 ft=Y, 7,000 ft=Y, 8,000 ft=Y, 9,000+ ft=?. Water need: L-M; sun/shade: S/PS; mature height: 1-2’; approximate bloom: Jun.
