Skip to content

Help us continue to build this resource.

Iris versicolor

Blue iris, Northern blue flag iris

Plant Details

Common Name: Blue iris, Northern blue flag iris
Family: Iridaceae (iris family)
Mature Height: 2 - 5'
Sun Requirement: Sun, Sun to part shade
Moisture Requirement: Moist
Flower Color: White, Blue, Violet
Bloom Time: Early summer (June - July), Mid summer (July - August)

Iris versicolor blue iris
Iris versicolor blue iris
Iris versicolor blue iris
Iris versicolor blue iris
Iris versicolor blue iris

Click on images to view larger versions


Iris is the Greek goddess of the rainbow; versicolor is Latin for variously colored. The common name ‘flag’ is from the Middle English word flagge, meaning rush or reed.

Native Habitat

Wet meadows, stream banks, marshes and swamps.

Garden Uses

Prefers moist to wet soil, growing well in rain gardens, marshes and on stream or pond banks, where it tolerates near-complete submergence. Generally care-free, and can also be easily grown and showy in sun to part-shade borders or naturalized in moist meadows.


This lovely purple iris is common in northern wetlands. Generally vigorous and easy to grow, it is clump-forming, with each clump spreading to 2-3 feet.

Leaves and Stems

Growing to a height of 2-3 feet, stems are sturdy and straight, while leaves are blade-like (lanceolate), approximately one inch at the widest mid-point and tapering on ends. Leaves rise both from a basal cluster and alternately on the stems, with edges set against the stem. Veins are parallel. Both leaves and stems are green to blue-green.


Classic iris shape, in any shade of blue-violet to purple, or, rarely, white. The 3 outward curling petals (referred to as ‘falls’), may be veined with white, and generally each measure up to 2 inches in length. The 3 petal-like sepals (referred to as ‘standards’) are always yellow-based. The 3 broad pollen-receptive stigma cover the pollen-producing anthers, improving insect-mediated pollination. The ovary is below the base of the petal attachment. Typically 3-5 blooms occur consecutively or sequentially on each stem.


Green to brown capsule, 1/2 to two inches long, splitting along 2 or more seams when dry to release 2 or more seeds.

Animal Associates

Popular with hummingbirds and insect pollinators. Poisonous to livestock. Deer tolerant. Can be damaged by iris borers.


Spreads both by self-seeding and extensions of rhizomes. Easily propagated by seed or by division post-flowering, or in autumn.

Ethnobotanical Uses

Historically used for medicinal purposes, it is now identified as toxic to humans, and a source of both mild skin irritation on contact and digestive upset if ingested.

Garden Location

Library Garden (see garden map)

Anecdotal Information

Related native North American species include the smaller southern Iris virginica, and the Atlantic coastal Iris prismatica, which has slimmer, more grass-like leaves.


Lady Bird Johnson Wildflower Center 

Missouri Botanical Garden

Native Plant Trust 

Plant Profile by Kate O’Dell