Flower profile
Yellow iris
Iris pseudacorus
Yellow iris is a wildflower that USDA PLANTS lists as introduced in the lower 48 states. In Washington it's most often seen in bloom in May–June.
*iNaturalist research-grade observations, as of October 17, 2026.
On our lists for: Washington
Quick look
Iris pseudacorus, the yellow flag, yellow iris, or water flag, is a species of flowering plant in the family Iridaceae. It is native to Europe, western Asia and northwest Africa. Its specific epithet pseudacorus means "false acorus", referring to the similarity of its leaves to those of Acorus calamus, as they have a prominently veined mid-rib and sword-like shape. However, the two plants are not closely related.
- It belongs to the Iridaceae family. iNaturalist
- USDA PLANTS describes it as an herb (forb) with a perennial life cycle. USDA PLANTS
- USDA PLANTS lists it as introduced in the lower 48 states and records it in 40 states. USDA PLANTS
- NatureServe lists it as not native to Washington. NatureServe
- In Washington, most iNaturalist sightings of it in flower come in May–June. iNaturalist
- iNaturalist has 2,035 research-grade sightings of it in Washington, ranking #91 among the 110 flowers on our Washington list. iNaturalist
State flower gift ideas
This one is a regulated invasive plant, so here are state flower gifts instead.
🌱 Sample spot. Handmade gift picks from independent shops will appear here once our shop partnership is approved. These cards are placeholders, not real products.
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State flower print
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Birth-flower necklace
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Wildflower seed favors
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Botanical tea towel
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Pressed-flower frame
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Flower-garden mug
When does it bloom?
In Washington, most flowering sightings come in May–June.
Conservation status
- Federal (U.S. ESA)
- Not listed No U.S. Endangered Species Act listing in the USFWS ECOS database. USFWS ECOS
- NatureServe global
- GNR Not yet ranked worldwide. NatureServe
- Washington
- No list Washington has no state law listing endangered or threatened plants (the Washington Natural Heritage Program's rare plant list isn't regulatory), so we show NatureServe's Washington ranks instead. NatureServe: SNA, not applicable (usually because it isn't native there) in Washington.
- Rare elsewhere
- No other U.S. state ranks it S1, S2, SH or SX.
Checked October 17, 2026. Rankings and lists can change, so follow the links for the latest.
Can you eat it?
NC State Extension lists it as poisonous to humans (severity: low). Symptoms they list: “Salivation, vomiting, drooling, lethargy, diarrhea. Highest concentration in rhizomes” NC State Extension
ASPCA's entry “Flag” (Iris species), which covers the whole genus, lists it as toxic to dogs, cats and horses. Signs include: Salivation, vomiting, drooling,lethargy, diarrhea. Highest concentration in… ASPCA
🌿 Never eat a wild plant unless you're certain of its ID; this isn't medical advice. Worried about a person? Call Poison Control at 1-800-222-1222. Worried about a pet? Call your vet.
Where does it grow?
USDA PLANTS records yellow iris in 40 states plus Washington, D.C.
recorded by USDA PLANTS on our state lists not recorded
See the full list of states
Alabama, Arkansas, California, Connecticut, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New York, North Carolina, Ohio, Oregon, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin; District of Columbia.
Washington counties with USDA records: Chelan, Clallam, Cowlitz, Ferry, Grant, Grays Harbor, Island, Jefferson, King, Kitsap, Kittitas, Lewis, Mason, Pacific, Pend Oreille, Pierce, San Juan, Skagit, Snohomish, Stevens, Thurston, Wahkiakum, Walla Walla, Whatcom.
More Washington flowers
Sources
- USDA, NRCS. PLANTS Database, profile IRPS.
- iNaturalist, Iris pseudacorus: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
- Wikipedia, Iris pseudacorus (lead quoted under CC BY-SA 4.0).
- Washington: Washington State noxious weed list (WAC 16-750-005, -011, -015).
- USFWS, ECOS species database (ESA listing check), October 17, 2026.
- NatureServe Explorer, Iris pseudacorus (global and state ranks).
- Edibility and toxicity: NC State Extension; ASPCA.
- Photo: Juan C. Espinosa via iNaturalist · CC BY 4.0 · resized.