FireApproved

United States / Grow / false indigo bush

false indigo bush (Amorpha fruticosa)
Photo: (c) Sandy Wolkenberg, some rights reserved (CC BY) (CC BY), via iNaturalist. Species-typical, not necessarily this cultivar.

false indigo bush

Amorpha fruticosa · Fabaceae · also called Indigo-bush · 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, false indigo bush is generally rated fire resistant.

Ohio State and Virginia Tech both give it their low-flammability rating, while Oregon State profiles it among plants suited to fire-resistant landscaping in the Willamette Valley. Arizona’s extension service also recommends it above 3,000 feet.

The agreement reaches beyond those regions. New Mexico’s Forestry Division includes false indigo bush on its FireWise list from 4,000 through 7,000 feet, marks suitability at 8,000 feet as uncertain, and does not recommend it at 9,000 feet or higher. A USDA Forest Service plant selector for the eastern United States is slightly more cautious, rating it Moderately Firewise, the second category on a four-point scale.

These findings come from expert and compiled landscaping guides rather than a published ignition experiment, so they support plant selection more directly than they explain combustion. Still, the pattern is unusually consistent across the Midwest, Mid-Atlantic, Southwest, Pacific Northwest, and eastern United States. False indigo bush is a full-sun shrub with high water needs, and regional growing conditions still matter. The practical conclusion is that it is a reasonable fire-resistant choice where local elevation and site requirements suit it, though the USDA’s moderate rating argues against treating it as nearly nonflammable.

Form
shrub
Mature height
~10 ft
Light
Full sun
Water need
high
Rated in
Arizona above 3,000 feet / interior Southwest; New Mexico; Ohio / Midwest; Oregon (Willamette Valley) +2
On this lot

1. Fire evidence and conditions

Fire evidence
Fire-resistant — location does not change the cited classification.
Placement evidence
3 source placement records; source schemes remain separate.
Evidence regions
Arizona above 3,000 feet / interior Southwest; New Mexico; Ohio / Midwest; Oregon (Willamette Valley); Virginia / Mid-Atlantic; eastern US
Typed publication scope: 5 scopes across 5 cited fire sources
  • FireWise Plant List for New Mexico · Official scoped edition
    • NM; partial normalized coverage · 2003-10-08

      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.

  • Firewise Landscaping (OSU Extension Bulletin 921) · Official scoped edition
    • OH; partial normalized coverage · 2006-03-01

      Ohio State University Extension Bulletin 921 is an Ohio publication that describes Ohio fire seasons and landscape conditions and labels nativity to Ohio. FireApproved publishes 352 exact source-owning plant records from its eight rated tables. This historical publication scope does not assert current extension endorsement or that a listed plant suits every Ohio site.

  • Fire-resistant Landscape Plants for the Willamette Valley (EM 9103) · Official scoped edition
    • 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.

  • FIREWISE Plant Materials for 3,000 ft. and Higher Elevations (AZ1289) · Official scoped edition
    • Arizona at or above 3,000 feet (AZ footprint); partial normalized coverage · 2011-12-01

      AZ1289 is explicitly limited to Arizona elevations of 3,000 feet and higher. FireApproved publishes 69 exact owners as regional Arizona context, retaining every water and elevation condition. It is never promoted to statewide low-desert guidance or an independent Tier 1 vote.

  • Virginia Firescapes — Firewise Landscaping for Woodland Homes (430-300) · Official scoped edition
    • VA; partial normalized coverage · 2009-04-15

      Virginia Cooperative Extension's publication opens with Virginia wildfire conditions, identifies its Virginia Firewise Landscaping Task Force, and labels plants native to Virginia. FireApproved publishes 306 exact source owners. Publication scope does not establish parcel suitability or current endorsement of this archived 2009 list.

2. Why this plant is relevant here

State distribution
Documented in AL, AR, AZ, CA, CO, CT, DC, DE, FL, GA, IA, ID, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, NC, ND, NE, NH, NJ, NM, NY, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VA, VT, WA, WI, WV, WY.
Native range
Current cited native range in AL, AZ, CA, CO, FL, ID, IL, KY, MD, MN, ND, NM, OR, PA, TN, TX, UT, VT, WA, WI, WY.
Introduced / established
1 sourced range or established record. This is not an invasive warning.
USDA hardiness
Documented minimum 3a; no upper limit is documented.

3. Legal, ecological, and broader status

Legal-list status
1 legal-list record; the Place chip matches exact scope.
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.

Current native

21

exact source areas

Current introduced

1

exact source area

Qualified

0

doubtful or extinct source rows

21 native source areas · World Checklist of Vascular Plants, version 16 v16, as of 2026-06-04
  • Alabama (AL)
  • Arizona (AZ)
  • California (CA)
  • Colorado (CO)
  • Florida (FL)
  • Idaho (ID)
  • Illinois (IL)
  • Kentucky (KY)
  • Maryland (MD)
  • Minnesota (MN)
  • North Dakota (ND)
  • New Mexico (NM)
  • Oregon (OR)
  • Pennsylvania (PA)
  • Tennessee (TN)
  • Texas (TX)
  • Utah (UT)
  • Vermont (VT)
  • Washington (WA)
  • Wisconsin (WI)
  • Wyoming (WY)
1 introduced source area · World Checklist of Vascular Plants, version 16 v16, as of 2026-06-04
  • New York (NY)

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.

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.

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)

  • FIREWISE Plant Materials for 3,000 ft. and Higher Elevations (AZ1289) — University of Arizona Cooperative Extension · 2011 revision · original source Corroboration Compilation lineage: csu-nmsu-firewise

    “listed FIREWISE plant material”

    Listed among fire-resistant plant materials for Arizona above 3,000 feet.

  • FireWise Plant List for New Mexico — New Mexico Energy, Minerals and Natural Resources Department, Forestry Division · 2003 Forestry Division PDF · original source Corroboration Compilation lineage: csu-nmsu-firewise

    “FireWise Plant List for New Mexico”

    Listed as Amorpha fruticosa (False indigo, indigobush) in Shrubs. Printed elevation cells: 4,000 ft=Y, 5,000 ft=Y, 6,000 ft=Y, 7,000 ft=Y, 8,000 ft=?, 9,000+ ft=N. Water need: M-H; sun/shade: S/PS; mature height: 2-3’; approximate bloom: May- July.

Mid-scale / conditional (1)

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

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

Amorpha fruticosa (Indigo-bush). FireApproved. https://fireapproved.com/plants/amorpha-fruticosa/. Last verified 2026-08-23.