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Mat penstemon is rated fire resistant on limited evidence, including an eight-point score and regional ground-cover recommendations.
Penstemon caespitosus appears with a fire-resistance score of eight in Idaho's database. Colorado's ignition-resistant plant table also prints eight for mat penstemon. Colorado explains that its method comes from Idaho and ranks plants on a zero-to-ten scale, with higher numbers indicating lower ignitability. The matching score therefore has a shared methodological background.
Fremont County puts mat penstemon in its Firewise ground-cover selection. Its advice makes plant choice, spacing, and maintenance part of the same landscape decision. That recommendation adds a regional planting use to the numerical assessment without creating a new score.
For a ground-cover bed, the useful combination is the favorable assessment and the work needed to maintain the planting. Colorado calls for regular watering and preventing dead material from accumulating regardless of a plant's ignition rating. Mat penstemon's score supports considering it; it does not replace those practical requirements.
Form
groundcover
Rated in
Black Hills, South Dakota; Colorado / Rocky Mountain Front Range; Fremont County, Wyoming; 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.
Black Hills (SD footprint); partial normalized coverage
The page explicitly limits itself to the Black Hills, and NFPA Firewise's archived 2006 plant-list index files it under South Dakota. FireApproved publishes 47 exact genus or species owners from 48 printed rows. This is bounded Black Hills context, not statewide South Dakota coverage or a finding that a plant suits a particular site.
Fremont County (WY footprint); partial normalized coverage · 2011-02-25
The source identifies itself as the Fremont County Firewise Plant List. FireApproved publishes its 92 exact source owners as Fremont County regional context. No methodology, current county endorsement, statewide Wyoming scope, or site-specific suitability is inferred.
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.
2. Why this plant is relevant here
State distribution
Documented in AZ, CO, ID, UT, WY.
Native range
Current cited native range in AZ, CO, UT, WY.
Introduced / established
USDA hardiness
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.
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)
Firewise Plant Material for the Black Hills: Flowers & groundcovers [black-hills-plant-form-table] (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 caespitosus (mat penstemon) with the preserved ignitability score.
“Fremont County Firewise Plant List — Penstemon caespitosus — Mat Penstemon”
Listed in the source's Ground Covers section; the page describes its listed Firewise plants as generally low-growing, low-debris, and relatively moist.
“Flowers & groundcovers: Mat penstemon — Pentemon caespitosus”
The introduction describes all table entries as fire-resistive plants that can be used in landscaping. Printed-name correction used for exact matching: Pentemon caespitosus -> Penstemon caespitosus.
