Iris versicolor (Northern Blue Flag)

A clumping iris native to marshes, swamps, and other wetland environments. Tall flowering stalks with blueish-purple blooms rise above narrow, sword-shaped leaves in late spring. Grows 2 to 3 feet tall and 2 to 3 feet wide. Prefers full sun to part shade and medium to wet soil.

Photos courtesy of Missouri Botanical Garden