Flower profile

Southern blue flag

Iris virginica

Southern blue flag (Iris virginica) is a flowering plant in the Iridaceae family, native in the lower 48 states, blooming mostly April–June across the U.S.

Native to South Carolina

Southern blue flag is a wildflower that USDA PLANTS lists as native in the lower 48 states.

27states where USDA records it

401SC sightings*

8,696U.S. sightings*

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

On our lists for: South Carolina

Quick look

Iris virginica, with the common name Virginia blueflag, Virginia iris, great blue flag, or southern blue flag, is a perennial species of flowering plant in the Iridaceae (iris) family, native to central and eastern North America.
From Wikipedia's article Iris virginica, 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 27 states. ^{USDA PLANTS}
NatureServe lists it as native to South Carolina. ^NatureServe
USDA PLANTS lists its flower color as blue. ^{USDA PLANTS}
USDA PLANTS gives its bloom period as spring. ^{USDA PLANTS}
USDA PLANTS lists a mature height of about 3.3 ft. ^{USDA PLANTS}
iNaturalist has 401 research-grade sightings of it in South Carolina, ranking #102 among the 171 flowers on our South Carolina list. ^iNaturalist

When does it bloom?

Flowering records by month in South Carolina (iNaturalist research-grade observations marked “Flowering”) (45 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: G5 Secure worldwide. ^NatureServe
South Carolina: No list South Carolina has no state law listing endangered or threatened plants, so we show NatureServe's South Carolina ranks instead. NatureServe: S5, secure in South Carolina.
Rare elsewhere: Other states where NatureServe ranks it rare or missing: KS (S1), NY (S1), OK (S1). (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, vomiting, abdominal pain, diarrhea, elevated temperature following ingestion; skin irritation upon contact with seeds, rootstock, or cell sap.” ^{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 Southern blue flag in 27 states plus Washington, D.C.

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recorded by USDA PLANTS on our state lists not recorded

See the full list of states

Alabama, Arkansas, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, West Virginia, Wisconsin; District of Columbia.

South Carolina counties with USDA records: Aiken, Allendale, Bamberg, Barnwell, Berkeley, Charleston, Cherokee, Clarendon, Colleton, Darlington, Dillon, Dorchester, Georgetown, Greenville, Hampton, Horry, Jasper, Lexington, Marion, McCormick, Spartanburg, Sumter, Williamsburg.

Growing conditions

USDA PLANTS gives Southern blue flag a low shade tolerance, none drought tolerance and high moisture use. It is rated for soil pH 4.8 to 7.3 and winter lows down to 12 °F.

Shade tolerance: Low
Drought tolerance: None
Moisture use: High
Soil textures it is adapted to: medium, fine
Soil pH range: 4.8 to 7.3
Minimum temperature tolerated: 12 °F
Frost-free days needed (minimum): 200
Annual precipitation range: 45 to 65 inches
Minimum root depth: 6 inches
Salinity tolerance: None
Fertility requirement: Medium
Growth rate: Moderate
Lifespan: Moderate
Active growth period: Spring
Fruit or seed: Black · Summer to Fall
Can be propagated by: bulb, seed
Commercial availability: Routinely Available

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

Names, range and relatives

Native status by region (USDA PLANTS): Canada: Native; Lower 48 states: Native.

County records: USDA PLANTS lists it in 668 counties across 27 states; the most are in Illinois (83), Indiana (63), Wisconsin (54).

Other Iris on Bloomipedia (11): Irises, Yellow iris, Dwarf crested iris, Douglas iris, Western blue flag, Northern blue flag iris, Oregon iris, 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 South Carolina flowers

Blue pigroot

Sisyrinchium micranthum

🌼 Blooms in SC: April–May

Dwarf iris

Iris verna

Native

🌼 Few flowering records in SC

American beautyberry

Callicarpa americana

Native

🌼 Blooms in SC: June–July

Sources

USDA, NRCS. PLANTS Database, profile IRVI.
iNaturalist, Iris virginica: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
Wikipedia, Iris virginica (lead quoted under CC BY-SA 4.0).
South Carolina: South Carolina State Plant Pest List, plants (S.C. Code Regs. 27-135; Clemson Dept. of Plant Industry).
USFWS, ECOS species database (ESA listing check), October 17, 2026.
NatureServe Explorer, Iris virginica (global and state ranks).
Edibility and toxicity: NC State Extension; ASPCA.
Photo: Raven Dandridge via iNaturalist · CC BY 4.0 · resized.