This is Dalea purpurea, also known as Purple Prairie Clover, and Violet Prairie Clover. This butterfly plant can grow up to 3 feet high in some places and likes to live in full sun, or partial shade, or anything in between. It blooms in the middle of the Summer where it is very popular with the bees, birds, and butterflies. The roots are edible and the leaves can be dried and used to make tea. Dalea purpurea is a larval host plant for the Marine Blue, Reakirts Blue, Clouded Sulphur, Orange Sulphur, and Southern Dogface butterflies. USDA Hardiness Zones 3 to 9.