|In summer, this group produces corymbs up to 6 inches across in colors ranging from cream, yellow, pink, scarlet, salmon, lilac, and purple. Clump-forming and generously blooming perennials that reach 18 inches tall and about 24 inches across. Evergreen fern-like leaves are grayish-green, and pinnate. This heat and drought tolerant perennial has a fiberous root system and can become invasive. Divide annually to maintain. Butterflies are attracted to this plant. Good cut flower that dries well, too.