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United States / Grow / western yarrow

western yarrow (Achillea tomentosa)
Photo: (c) Alessia Guggisberg, some rights reserved (CC BY) (CC BY), via iNaturalist. Species-typical, not necessarily this cultivar.

western yarrow

Achillea tomentosa · Asteraceae · all Achillea records · also called Woolly yarrow · Wikipedia

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Is this one for your yard?

Enter your ZIP to see whether this is legal to plant in your state, and whether it survives your winter.

Yes, western yarrow is rated fire resistant by five sources across several regions.

Fire Safe Marin, Montana State University Extension, the King County Forestry Program, and Michigan State University Extension each include Achillea tomentosa on a fire-resistant or wildfire-resistant plant list. The Nevada source reaches the same conclusion through a compilation: it includes plants favorably rated by at least two named western sources, and western yarrow appears in four of them. Agreement from California, Nevada, Montana, western Washington, and Michigan makes the conclusion broader than a recommendation tied to one climate.

The sources do not all use the same method. Four are expert-curated lists, while the University of Nevada Cooperative Extension compiles findings from earlier western publications. Fire Safe Marin does not describe an experimental rating method. Fire Safe Marin also warns that a fire-resistant listing does not replace careful placement, spacing, irrigation, and removal of dead material. In other words, resistant does not mean fireproof or maintenance-free.

Western yarrow is a groundcover in the aster family. It reaches about three feet at maturity, requires moderate water, and is listed for USDA zones 3a through 7b. For a homeowner choosing among landscape plants, the consistent verdict supports treating western yarrow as fire resistant while still managing the plant and its surroundings carefully.

Form
groundcover
Mature height
~3 ft
Water need
moderate
Rated in
Marin County, California; Michigan / Great Lakes; Montana / Northern Rockies; Nevada / Great Basin +1
On this lot

1. Fire evidence and conditions

Fire evidence
Fire-resistant — location does not change the cited classification.
Fire-performance conditions
1 condition stated in cited fire-evidence rows.
Evidence regions
Marin County, California; Michigan / Great Lakes; Montana / Northern Rockies; Nevada / Great Basin; western WA
Typed publication scope: 5 scopes across 5 cited fire sources
  • Fire-Resistant Plants Common to Marin County · Official scoped edition
    • Marin County (CA footprint); partial normalized coverage · 2019-01-01

      The publication is explicitly limited to plants common to Marin County. FireApproved publishes 104 exact owners as Marin regional context while retaining its placement, spacing, irrigation, and maintenance boundary. It is not statewide California guidance or parcel suitability.

  • Firewise Plants for the Puget Sound Basin · Official scoped edition
    • Puget Sound Basin (WA footprint); partial normalized coverage · 2011-01-01

      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.

  • Wildfire-resistant Landscape Plants for Michigan (Extension Bulletin E2948) · Official scoped edition
    • MI; partial normalized coverage · 2007-01-01

      Michigan State University Extension Bulletin E2948 is explicitly a list of wildfire-resistant landscape plants for Michigan and includes a Michigan-native field. FireApproved publishes 221 exact GBIF owners from 226 represented source rows and holds 15 complex or non-exact rows. This dated publication scope is not a current site-suitability determination.

  • Fire-Resistant Plants for Montana Landscapes (MontGuide MT200101AG) · Official scoped edition
    • MT; partial normalized coverage · 2022-04-01

      The April 2022 MontGuide explicitly presents fire-resistant species adapted to Montana. FireApproved publishes 92 exact plant records from the source while retaining excluded genus, family, and unresolved rows; the guide itself says not every listed species grows in every part of the state.

  • A Compilation of Good Plant Choices for Nevada's High Fire Hazard Areas (SP-05-16) · Official scoped edition
    • NV; partial normalized coverage · 2005-01-01

      University of Nevada Cooperative Extension compiled plants suited to Nevada climate zones and reported favorably by at least two upstream firewise lists. FireApproved publishes 126 exact source owners at Nevada publication scope. The source explicitly makes no independent flammability determination, so these rows remain corroborative.

2. Why this plant is relevant here

State distribution
Documented in AK, AL, AR, AZ, CA, CO, CT, DC, DE, FL, GA, IA, ID, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, MT, NC, ND, NE, NH, NJ, NM, NV, NY, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VA, VT, WA, WI, WV, WY.
USDA hardiness
2 applicable cited hardiness statements overlap but have different boundaries; compare each complete source row.

3. Legal, ecological, and broader status

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.

Conditions in the fire evidence

These describe tested or rated plant material. They are not horticultural maintenance instructions.

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.

Recommends (5)

Corroboration (2 rows from 2 sources)
Same genus in the directory · the Achillea group page

Last verified 2026-08-23. JSON (CC BY 4.0)

Profiles: USDA PLANTS · GBIF · iNaturalist · Wikidata · Wikipedia · ITIS

Achillea tomentosa (Woolly yarrow). FireApproved. https://fireapproved.com/plants/achillea-tomentosa/. Last verified 2026-08-23.