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Onion (Allium) is consistently rated fire resistant for home landscaping.
The extension services of Oregon State, Washington State and the University of Idaho list it as fire resistant in USDA zones 4a to 8b, while FireSmart BC also approves it as a fire-resistant plant.
The agreement extends beyond the Northwest. The LSU AgCenter recommends onion for firewise landscaping in Louisiana, and King County includes Allium species, specifically chives and onion, among fire-resistant perennials. Idaho Firewise gives onion a score of 10 on its field-trial scale, the highest value and one the source considers acceptable at a minimum planting distance of 10 feet.
These five sources use different methods and serve climates ranging from Louisiana to British Columbia, yet all reach the same practical conclusion. Most make a yes-or-no recommendation, while Idaho’s score also connects resistance to planting distance. Together, they provide strong support for treating onion as a fire-resistant perennial, not as a plant that cannot burn. For a homeowner selecting plants near a house, onion belongs among the safer landscape choices while still following the spacing guidance attached to the rating.
Form
perennial
Rated in
British Columbia; Louisiana; OR/WA/ID; southern Idaho / Intermountain +1
On this lot
1. Fire evidence and conditions
Fire evidence
Fire-resistant — location does not change the cited classification.
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.
King County's current wildfire page links this list for the Puget Sound Basin. FireApproved publishes 82 exact source owners as basin context, not statewide Washington guidance or a site-specific recommendation.
LSU AgCenter calls these 31 ornamentals commonly used in Louisiana and recommended for Louisiana firewise landscaping efforts. FireApproved publishes 31 exact source owners, mostly at the source's genus grain. Undocumented curation remains corroborative and is not site suitability.
The October 2023 joint Pacific Northwest Extension publication explicitly names Oregon, Washington, and Idaho and publishes more than 150 plant profiles. FireApproved has normalized 155 exact plant records from the source; publication scope does not assert that every listed plant suits every site within the three states.
2. Why this plant is relevant here
State distribution
Documented in ID, OR, WA.
Native range
Introduced / established
USDA hardiness
Documented range 4–8.
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.
4–8 explicit range · whole zone precision · source stated
Source taxon: Allium · exact match.
Source location: Plant profile USDA hardiness zones field.
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.
FireSmart BC Plant Program: suitable for HIZ intermediate zone (10-30 m) [FireSmart BC Home Ignition Zone] (with its recommendation)
Fire Resistance of Plants Master Database: 10 ft minimum planting distance on flat terrain [Idaho minimum planting distance] (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.
