This delightful iris can be found in the wild across much of northeastern United States. It typically grows in moist swales and other damp locations, though I have found that it is quite tolerant of drier conditions. It is a beardless, blue iris that reaches 2 to 3 feet. The leaves are slender and sword shaped. Blooms appear in late spring to early summer. Like most irises, the bloom period is not exceptionally long but the foliage remains attractive all summer.
Blue Flag is an excellent choice for naturalizing and wildflower gardens. It is also at home in more formal settings. It will compete fairly well
with other plants and does not require division. Division can, however, be used as a means of obtaining new plants.