Master Gardeners of Northern Virginia

Promoting environmentally sound gardening practices for over 35 years!

Mertensia virginica en masse.
Mertensia virginica en masse. Photo © Mary Free
You are here: Home / Plants / Tried and True Native Plant Selections for the Mid-Atlantic / Perennials / Iris virginica (Virginia or Southern Blue Flag)

Iris virginica (Virginia or Southern Blue Flag)

Iris virginica, Virginia Blue Flag
Iris virginica, Virginia Blue Flag
Ruby-throated hummingbird feeds on native Iris versicolor.
Iris versicolor en masse in June

Note: Click on images to see enlarged photos, captions, and photo attributions.
On a mobile phone, click on the information symbol (circle with a letter ℹ︎ symbol).

Perennial Plants & Flower,* Colony with Hummingbird** Height: 1–3 feet Spread: 1–2 feet Bloom Color: Light blue to deep violet Characteristics Upright, clumping herbaceous perennial Weakly arching, bright medium green, sword- shaped basal leaves rise from shallow roots Blue flowers with darker purple veins and bright yellow signals bloom on tall stalks from May to July Green to brown fruit capsule Spreads by rhizomes to form colonies Attributes Tolerates clay soil, light shade, and flooding No serious pests–but snails may eat foliage and muskrats eat rhizomes–or diseases; deer and rabbits rarely damage Ethnobotanic, therapeutic, and herbal uses Attracts bees, butterflies, skippers, hummers Growing and Maintenance Tips Excellent Replacement for Soil Requirements: Wet, acidic soils Iris pseudacorus - Yellow Flag Iris Light Requirements: Sun Water Requirements: Moist, Wet *I. virginica is native in DC and in Prince George’s and Kent Counties in MD. In VA, it is frequent to locally common in the Coastal Plain and infrequent to rare inland. In NoVA, it is native to Fairfax and Prince William Counties. It is pictured in full form and close-up above. **I. versicolor is native in DC, DE, MD’s Anne Arundel and Calvert Counties, mostly the eastern and northwestern counties of PA, and northward into Canada. In VA, it is infrequent to rare in the mountains, northern Piedmont, and northern Coastal Plain. In NoVA, it is native in Fairfax and Loudoun Counties. It is pictured with a ruby-throated hummingbird above. Propagate by clump division in early fall when leaves begin to turn yellow (wear gloves) Use along water’s edge, in water garden, or in rain garden that is consistently moist to wet Hardiness: USDA Zones 5-9 developed by Master Gardeners of Northern Virginia, serving Arlington and Alexandria Images by Elaine Mills (top), Meadowlark Botanical Gardens and Mary Free (bottom), Fort Shantok, CT

Tried and True Native Plant Selections
for the Mid-Atlantic 

Print Version (Legal Size):
Iris virginica (Virginia or Southern Blue Flag)

The wetland species of Southern Blue Flag* and its close relative, Northern Blue Flag (Iris versicolor),** grow in fresh to mildly brackish tidal marshes and wet meadows of the Mid-Atlantic, but the former is mostly found from Virginia southward to Florida. Both native irises share similar growth habits and showy flowers that attract hummingbirds.

*Iris virginica is native in DC and in Prince George’s and Kent Counties in MD. In VA, it is frequent to locally common in the Coastal Plain and infrequent to rare inland. In NoVA, it is native to Fairfax and Prince William Counties. It is pictured in full form and close-up above.

**Iris versicolor is native in DC, DE, MD’s Anne Arundel and Calvert Counties, mostly the eastern and northwestern counties of PA, and northward into Canada. In VA, it is infrequent to rare in the mountains, northern Piedmont, and northern Coastal Plain. In NoVA, it is native in Fairfax and Loudoun Counties. 

Northern Blue Flag is native to Fairfax and Loudoun Counties and is similar in growth habit to Southern Blue Flag. Their flowers, which are difficult to tell apart, attract hummingbirds. Learn more about Pollinators.
Video © Mary Free

Learn more about other Mid-Atlantic plants: 
Tried and True Native Plant Fact Sheets

Back to Top