One is Iris versicolor, often called northern blue flag or harlequin blue flag, and the other is Iris virginica, often called the southern blue flag. Both types are aquatic plants that grow from clumps of rhizomes. These irises are prevalent throughout the eastern United States, with I. virginica common from Virginia to Texas and I. versicolor familiar from Tennessee up into Canada. Both types of iris are a lovely shade of blue and grow quickly in wet soil conditions.
Blue Flag Iris prefers Swampy, Muddy Environments and is an Excellent Plant to have Along Pond Borders or in Areas with Poorly Draining Soil
However, note that the plants shouldn't be in more than 4 inches of water. Blue flag irises are not considered invasive, so they're an excellent choice if you want iris plants in your garden but live in an area where the yellow flower is an invasive problem.
Both types of iris produce showy flowers in spring. The northern iris is purple or blue-purple, and the southern iris is a much more clear blue with white and yellow accents toward the interior edges of the petals. Both irises grow in clusters of long, green leaves and stems, which provide a bright, fresh color for any garden.
Blue Flag Iris is a flowering perennial that makes large clumps of thick, creeping rhizomes
The stems usually have basal leaves that are more than 1 cm wide. The leaves resemble an overlapping flat fan. The Blue Flag Iris tends to be poisonous when consumed by humans and dermatitis is caused by the sap.
