wetland wildflower

Southern blue flag

Iris virginica

Also known as Virginia Iris, Great Blue Flag

Native to the Southeast

Coastal Plain from southeastern Virginia to Texas

Light Full sun Sun tolerance
Moisture Wet Moisture preference
Zones 3–9 Cold to heat range
Bloom Mar–Jun Flowering time
Height up to 3 ft to 0.9 m
Life cycle Perennial Annual to perennial

Full details, see below

In the garden

A wetland wildflower for full sun and wet soil. Its white flowers peak in June. At up to 3 ft, it suits rain gardens, pond edges, and damp low spots. Hardy in USDA zones 3–9.

Growing conditions

Light

Full sun Partial shade Full shade

Moisture

Dry Moist Wet

Hardiness zones

Find your zone:

When it blooms

The Southern blue flag's white flowers bloom March to June, peaking in June. This early-summer display draws bees and butterflies.

Southern blue flag blooms white, pink & blueFoliage

Pollinators & wildlife

Bees Common Eastern Bumble Bee

also Eastern Carpenter Bee, Brown-belted Bumble Bee, Two-spotted Bumble Bee +2 more
American Bumble Bee, Orange-tipped Wood-digger
Butterflies Silver-spotted Skipper

also Viceroy, Peck's Skipper, Hobomok Skipper +3 more
Palamedes Swallowtail, Bronze Copper, Two-spotted Skipper
Flower flies The Merodon equestris Group also Eurimyia stipatus
Also visited by
- Hummingbirds: Ruby-throated Hummingbird

Butterflies that use this plant

Documented host and nectar records. Each links to a planting guide for that butterfly.

Full plant details

Where it grows

Habitat: WetlandThe wild plant community it grows in.
Native range: The SoutheastUnited States (10): AL, AR, FL, GA, LA, MS, NC, SC, TX, VA. Where it grows wild on its own, by state and province.
Native distribution: Coastal Plain from southeastern Virginia to TexasThe same native range, usually more exact than the state list, and often noting where it has spread beyond it.

Growing conditions

Light: Full sunHow much sun it takes, from full sun to full shade.
Moisture: WetThe soil dampness it prefers, from dry to wet.
Hardiness zones: USDA 3–9 · Canadian 4–7The cold-to-heat climate range it survives.
Soil: Moist, rich soilsThe soils it grows in naturally.
Soil pH: 4.8–7.3The acidity to alkalinity it tolerates (7 is neutral).
Soil quality: MediumHow rich a soil it needs. Many natives prefer lean soil and flop in rich beds.
Water use: HighHow thirsty it is, a rough guide to how often to water.
Salinity tolerance: NoneHow well it copes with salty soil, near roads or the coast.
Lime (CaCO₃) tolerance: LowHow well it copes with chalky, lime-rich soil.

Growth & form

Height: up to 3 ft (to 0.9 m)Typical mature height.
Life cycle: PerennialWhether it lives a single season (annual), two (biennial), or returns for years (perennial).
Growth rate: ModerateA relative ranking versus other plants of the same type (USDA), not an absolute rate.
Shape: ErectIts overall silhouette.
Root depth: 6+ in (15+ cm)How far the roots reach, a guide to drought resilience and transplanting.

Flowers, foliage & fruit

Type: WildflowerWhat kind of plant it is.
Bloom: Mar–JunWhen it flowers.
Flower color: White, Pink, BlueThe bloom color, or colors.
Fruit/Seeds: Capsule; ripens Apr–OctThe seed or fruit it sets after flowering.
Toxicity: None knownWhether any part is poisonous to people or pets.

Propagation & seed

Cold stratification: Not requiredWhether seed needs a cold, moist spell before it will germinate.
Propagation: Bulb, seedHow to start new plants.
Seed spread rate: SlowHow readily it self-sows. Slow or none means well-behaved, not a spreader.
Seedling vigor: MediumHow strongly young seedlings establish.
Vegetative spread: ModerateWhether it creeps outward or stays put in a clump.