Flower profile

Oregon iris

Iris tenax

Oregon iris (Iris tenax) is a flowering plant in the Iridaceae family, native in the lower 48 states, blooming mostly April–June across the U.S.

Native to Oregon

Oregon iris is a wildflower that USDA PLANTS lists as native in the lower 48 states. In Oregon it's most often seen in bloom in April–June.

3states where USDA records it

4,531OR sightings*

4,898U.S. sightings*

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

On our lists for: Oregon

Quick look

Iris tenax is a species of Iris, known by the common names tough-leaved iris, Oregon iris, or more colloquially, flag.
From Wikipedia's article Iris tenax, CC BY-SA 4.0.

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 3 states. ^{USDA PLANTS}
NatureServe lists it as native to Oregon. ^NatureServe
In Oregon, most iNaturalist sightings of it in flower come in April–June. ^iNaturalist
USDA PLANTS lists its flower color as purple. ^{USDA PLANTS}
USDA PLANTS gives its bloom period as mid spring. ^{USDA PLANTS}
USDA PLANTS lists a mature height of about 1.5 ft. ^{USDA PLANTS}
iNaturalist has 4,531 research-grade sightings of it in Oregon, ranking #31 among the 184 flowers on our Oregon list. ^iNaturalist

When does it bloom?

In Oregon, most flowering sightings come in April–June.

Flowering records by month in Oregon (iNaturalist research-grade observations marked “Flowering”) (843 records)

Conservation status

Federal (U.S. ESA): Not listed No U.S. Endangered Species Act listing in the USFWS ECOS database. ^{USFWS ECOS}
NatureServe global: G4 Apparently secure worldwide. ^NatureServe
Oregon: Not listed Not on Oregon endangered and threatened plants (OAR 603-073-0070). NatureServe: SNR, not yet ranked in Oregon. ^{OAR 603-073-0070}
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?

For peopleNot well documented

None of the sources we checked (NC State Extension (no page for this plant), USDA PLANTS) say whether it's edible or poisonous for people.

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 Oregon iris in 3 states.

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recorded by USDA PLANTS on our state lists not recorded

See the full list of states

California, Oregon, Washington.

Oregon counties with USDA records: Benton, Clackamas, Clatsop, Columbia, Coos, Curry, Douglas, Jackson, Lane, Lincoln, Linn, Marion, Multnomah, Polk, Tillamook, Union, Washington, Yamhill.

Growing conditions

USDA PLANTS gives Oregon iris a low shade tolerance, medium drought tolerance and medium moisture use. It is rated for soil pH 6.0 to 8.0 and winter lows down to -13 °F.

Shade tolerance: Low
Drought tolerance: Medium
Moisture use: Medium
Soil textures it is adapted to: coarse, medium
Soil pH range: 6.0 to 8.0
Minimum temperature tolerated: -13 °F
Frost-free days needed (minimum): 120
Annual precipitation range: 16 to 60 inches
Minimum root depth: 12 inches
Salinity tolerance: None
Fertility requirement: Medium
Growth rate: Moderate
Lifespan: Moderate
Active growth period: Spring and Summer
Fruit or seed: Brown · Spring to Summer
Can be propagated by: bulb, seed
Commercial availability: Contracting Only

From the USDA PLANTS characteristics data for IRTE. USDA ratings are general guidance for the species, not a guarantee for your garden.

Names, range and relatives

County records: USDA PLANTS lists it in 29 counties across 3 states; the most are in Oregon (18), Washington (9), California (2).

Other Iris on Bloomipedia (11): Irises, Yellow iris, Dwarf crested iris, Douglas iris, Western blue flag, Northern blue flag iris, Southern blue flag, Dwarf iris, Beach-head iris, Dwarf lake iris.

More from the Iridaceae family (14 on Bloomipedia; most observed first): Western blue-eyed grass, Blue pigroot, Grasswidow.

More Oregon flowers

Pacific trillium

Trillium ovatum

Native

🌼 Blooms in OR: March–May

Salal

Gaultheria shallon

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🌼 Blooms in OR: May–July

Thimbleberry

Rubus parviflorus

Native

🌼 Blooms in OR: May–June

Sources

USDA, NRCS. PLANTS Database, profile IRTE.
iNaturalist, Iris tenax: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
Wikipedia, Iris tenax (lead quoted under CC BY-SA 4.0).
Oregon: Oregon endangered and threatened plants (OAR 603-073-0070).
Oregon: Oregon noxious weed quarantine, A and B weeds (OAR 603-052-1200).
USFWS, ECOS species database (ESA listing check), October 17, 2026.
NatureServe Explorer, Iris tenax (global and state ranks).
Edibility and toxicity: ASPCA.
Photo: Judi Sanders via iNaturalist · CC BY 4.0 · resized.