Hardy, North American, spring-blooming perennial
Description: Showy, bluish-purple, wide-spreading flowers in branched clusters of two or three; falls are often blotched in yellow or purple-veined
Habit: Forms vigorous clumps of 2- to 3-foot, sword-shaped leaves; spreads to 2 feet
Culture: Prefers moist, humus-rich soil and is best suited to wet or boggy situations; grows in full sun to light shade
Hardiness: Cold hardy to USDA Zone 3
This water-loving Iris is native to eastern Canada and northeastern and north central United States. It was introduced into Europe from North America in 1732. The Philadelphia nursery of John Bartram & Son offered the wild Blue Flag along with four other native Iris species in 1807. Another prominent Philadelphia nurseryman, Bernard McMahon, listed it as "Various-coloured iris" in the appendix of the American Gardener’s Calendar, 1806.