Bloomipedia
Northern blue flag iris (Iris versicolor)
Photo: Cyndy Sims (Parr) via iNaturalist · CC BY 4.0 · resized

Flower profile

Northern blue flag iris

Iris versicolor

Native in the lower 48

Northern blue flag iris is a wildflower that USDA PLANTS lists as native in the lower 48 states. It's on our flower lists for 2 states, and across the U.S. it's most often seen in bloom in May–July.

19states
2of our state lists
8,962U.S. sightings*

*iNaturalist research-grade observations, as of October 17, 2026.

On our lists for: Maine, New Hampshire

Quick look

Iris versicolor or Iris versicolour is also commonly known as the blue flag, harlequin blueflag, larger blue flag, northern blue flag, and poison flag, plus other variations of these names, and in Great Britain and Ireland as purple iris.

  • 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 native in the lower 48 states and records it in 19 states. USDA PLANTS
  • NatureServe lists it as native to Maine and New Hampshire. NatureServe
  • In Maine, most iNaturalist sightings of it in flower come in June–July. iNaturalist
  • In New Hampshire, most iNaturalist sightings of it in flower come in May–July. iNaturalist
  • iNaturalist has 1,269 research-grade sightings of it in Maine, ranking #50 among the 110 flowers on our Maine list. iNaturalist
  • iNaturalist has 440 research-grade sightings of it in New Hampshire, ranking #83 among the 109 flowers on our New Hampshire list. iNaturalist

Northern blue flag iris gift ideas

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🌱 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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When does it bloom?

Flowering records by month across the U.S. (iNaturalist research-grade observations marked “Flowering”) (1,729 records)
Bloom time in each of our 2 states
StateTypePeak bloomSightings*
MaineNativeJune–July1,269
New HampshireNativeMay–July440

Conservation status

Federal (U.S. ESA)
Not listed No U.S. Endangered Species Act listing in the USFWS ECOS database. USFWS ECOS
NatureServe global
G5 Secure worldwide. NatureServe
Maine
Not listed Not on Maine Rare Plant List (Maine Natural Areas Program, 2021). E and T are Maine's official endangered and threatened plants (12 M.R.S.); SC and PE are tracking categories. NatureServe: SNR, not yet ranked in Maine. Maine rare plant list
New Hampshire
Not listed Not on New Hampshire Official Rare Plants List (Ncr 312, eff. Jan 1, 2020). NatureServe: SNR, not yet ranked in New Hampshire. NH Ncr 312
Rare elsewhere
Other states where NatureServe ranks it rare or missing: DC (S1), ID (S2). (S1 critically imperiled, S2 imperiled, SH possibly extirpated, SX presumed extirpated.)

Checked October 17, 2026. Rankings and lists can change, so follow the links for the latest.

Can you eat it?

For peoplePoisonous to people

NC State Extension lists it as poisonous to humans (severity: low). Poisonous parts: roots, sap/juice, seeds. Symptoms they list: “CAUSES ONLY LOW TOXICITY IF EATEN. SKIN IRRITATION MINOR, OR LASTING ONLY FOR A FEW MINUTES. Nausea, salivation, vomiting, abdominal pain, lethargy, diarrhea, elevated temperature following ingestion; skin irritation upon contact with seeds, rootstock, or…” NC State Extension

For petsToxic to dogs, cats and horses

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 Northern blue flag iris in 19 states plus Washington, D.C.

recorded by USDA PLANTS on our state lists not recorded

See the full list of states

Connecticut, Delaware, Idaho, Illinois, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, Virginia, Wisconsin; District of Columbia.

Maine counties with USDA records: Androscoggin, Aroostook, Cumberland, Franklin, Hancock, Kennebec, Knox, Lincoln, Oxford, Penobscot, Piscataquis, Sagadahoc, Somerset, Waldo, Washington, York.

New Hampshire counties with USDA records: Belknap, Carroll, Cheshire, Coos, Grafton, Hillsborough, Merrimack, Rockingham, Strafford, Sullivan.

More Maine flowers

Roses (genus Rosa) (Rosa)

Roses (genus Rosa)

Rosa

★ NY state flower🌷 Garden flower

🌼 Blooms in ME: June–October
Canadian bunchberry (Cornus canadensis)

Canadian bunchberry

Cornus canadensis

Native

🌼 Blooms in ME: May–July
Rugosa rose (Rosa rugosa)

Rugosa rose

Rosa rugosa

Introduced

🌼 Blooms in ME: June–October

Sources