Enter your ZIP to see whether this is legal to plant in your state, and whether it survives your winter.
Kidney saxifrage has several favorable fire-resistance recommendations, although the matching Idaho and Colorado scores share a methodological connection.
Idaho Firewise assigns Saxifraga hirsuta a score of 8. Its scale connects that score to a suggested minimum distance of 30 feet from a home. Colorado's 2025 fact sheet also prints 8 on a scale whose higher values mean lower ignitability. Colorado credits Idaho materials as the basis of its scoring approach; matching numbers therefore do not establish separate trials of the plant.
Oregon State University's Willamette Valley guide profiles Saxifraga hirsuta among fire-resistant perennials, and FireSmart BC includes it in its favorable plant chart. Those listings add regional plant-selection guidance without supplying another numerical test result.
The recommendations consistently favor kidney saxifrage. Keeping the Idaho distance meaning and the relationship between the scoring sources visible makes that agreement more useful than simply counting four favorable publications.
Form
perennial
Rated in
British Columbia; Colorado / Rocky Mountain Front Range; Oregon (Willamette Valley); 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.
Willamette Valley (OR footprint); partial normalized coverage · 2015-02-01
OSU Extension says EM 9103 highlights fire-resistant plants that thrive under Willamette Valley growing conditions. FireApproved publishes 172 exact owners only as valley context. The guide shares the PNW 590 lineage and is not a second independent vote or statewide site clearance.
2. Why this plant is relevant here
State distribution
Documented in ID.
Native range
Introduced / established
USDA hardiness
Documented range 5–8.
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.
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.
5–8 explicit range · whole zone precision · source stated
Source taxon: Saxifraga hirsuta · exact match.
Source location: Saxifrage profile (PDF page 85).
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)
FireSmart BC Plant Program: suitable for HIZ intermediate zone (10-30 m) [FireSmart BC Home Ignition Zone] (with its recommendation)
Fire-resistant Landscape Plants for the Willamette Valley: Saxifrage profile (PDF page 85) [osu-em-9103-profile] (with its recommendation)
Ignition-Resistant Landscape Plants: suitable for defensible-space zones 1-2 (score 8+) [CSU defensible-space zone] (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-resistant plants that thrive in Willamette Valley growing conditions”
The perennials profile lists Saxifraga hirsuta as Saxifrage. The profile prints USDA Hardiness Zone: 5–8.
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 Saxifraga hirsuta (saxifrage) with the preserved ignitability score.
