Iris versicolor (Blue Flag)
The name "flag" is from the middle English, flagge," which means "rush" or "reed, and that's why Iris versicolor, native to the swamps, marshes, and wetlands of the northeastern United States, is commonly known as "Blue Flag." Blue Flag grows to about two feet with violet-blue flowers in late spring and prefers moist conditions and sun in Zones 3-9. Note: My Iris versicolor is grown from seeds from SIGNA seed exchange. All are from named varieties but since they are seed grown, there may be variations - all a plus, if you ask me. Below are two more examples.