It is a species of Iris native to North America, in the Eastern United States and Eastern Canada. It is common in sedge meadows, marshes, and along streambanks and shores. The specific epithet versicolor means "variously colored".

Iris versicolor is also commonly known as the blue flag, harlequin blueflag, larger blue flag, northern blue flag, and poison flag, plus other variations of these names, and in Britain and Ireland as purple iris.

Iris versicolor is a flowering perennial plant. It tends to form large clumps from thick, creeping rhizomes. Flowers are usually light to deep blue (purple and violet are not uncommon) and bloom during May to July.

The iris is the official state flower of the U.S. state of Tennessee. This designation was made in 1933 by the state legislature. Although the law does not specifically define a type of iris, it is generally accepted that the purple iris is the state flower.

The blue flag is the provincial flower of Quebec, having replaced the Madonna lily which is not native to the province.

The Purple Iris is the official flower of Kappa Pi International Honorary Art Fraternity.

Seeds are large and fresh.

Type: Hardy perennial

Hardiness zones: 3-9

Seeds per packet: 15