|Hardy and strong rhizome producing perennial with simple, toothed, lance-shaped dark green leaves. Reaches 30 to 36 inches tall. From early to late summer, double white flowerheads form loose corymbs slightly larger than the species. This heat and drought tolerant perennial has a fiberous root system and can become invasive. Divide to maintain. Butterflies are attracted to this plant. Good cut flower that dries well, too.