Blue Flag Iris

Blue flag iris is a clump-forming North American native with upright, blue-green leaves and blue-violet flowers marked with white and yellow. It grows naturally in marshes and wet meadows and suits pond margins, rain gardens, or other consistently moist sites. ## Flowers and placement In late spring and early summer, flower stalks rise above the foliage and carry several showy iris flowers. Each bloom has three upright standards and three broad falls, often with a yellow signal near the throat. The [NC State Extension Plant Toolbox](https://plants.ces.ncsu.edu/plants/iris-versicolor/) describes its wetland habitat, flowering, 3–9 USDA hardiness range, and low-severity toxicity if eaten. The [Morton Arboretum profile](https://mortonarb.org/plant-and-protect/trees-and-plants/blue-flag-iris/) reports a typical size of 2–2½ feet tall and wide and recommends moist to wet soil with full to partial sun. It can grow in shallow fresh water, including pond containers. ## Seasonal character The upright leaf fans create a strong vertical texture before and after bloom. Blue flag iris spreads by rhizomes and self-seeding, gradually forming clumps; allow room for that growth near paths and water edges. Gloves are sensible when dividing because plant sap and rhizomes may irritate skin, and ingestion can cause mild poisoning. ## Maintenance Water during dry periods, particularly while stems are developing. Divide clumps after flowering when they become crowded, and remove frost-damaged leaves in late fall. Watch for iris borers, thrips, aphids, and leaf or blossom blight.