A variable, clump-forming, deciduous perennial with palmately-lobed, toothed, dark green leaves and, in summer, erect, branching stems bearing umbels of small, green, pink, or reddish-purple flowers surrounded by white to greenish-white bracts, sometimes flushed blue, purple, or red.
Height 1m (3ft), Spread 50cm (1.5ft), 2-5 years to maturity.