Southern blue flag is a native North American iris that brings wetland beauty to gardens from zones 5 through 9. This perennial grows 24 to 36 inches tall and produces fragrant, showy blue flowers in June that make excellent cut flowers. Unlike many ornamentals, it thrives in the wet, boggy conditions that challenge other plants, spreading by rhizomes to form naturalized colonies over time. Butterflies visit the blooms, and the plant stands up to deer and clay soil with minimal maintenance.
Full Sun
Moderate
5-9
36in H x 24in W
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Moderate
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Southern blue flag evolved in the wetlands and marshes of the eastern United States and southern Canada, where it naturally tolerates the standing water and acidic, sandy soils that defeat most garden plants. The fragrant blue flowers appear in June and attract butterflies while remaining untouched by deer. This iris grows well in full sun and handles wet soil, clay, and even shallow water up to 6 inches deep, making it an exceptional choice for rain gardens and boggy spots where conventional plants struggle.
Southern blue flag is grown primarily to naturalize wetland areas, restore native plant communities, and create rain gardens that handle excess water. Its fragrant flowers are valued as cut flowers for indoor arrangements, and its showy June blooms attract butterflies, making it popular in pollinator gardens. The plant thrives in water gardens and along stream banks where it stabilizes soil and creates habitat.
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“Iris virginica is native primarily to wetlands, marshes, lake sides, stream banks, and other moist, open areas across the eastern half of the United States and southern Canada. Two geographic varieties exist: I. virginica var. virginica, which inhabits the Atlantic coastal plain from Virginia to peninsular Florida and west to Texas, and I. virginica var. shrevei, found in the central United States and southern Canada from Arkansas northward. The plant has been part of the landscape for centuries, with its distribution shaped by the regions where water persists year-round.”