This herbaceous perennial has fluffy spikes of white, pink, red or purple flowers in the summer. Most of the species which are native to Korea, China and Japan have delicate, compound leaves with the exception of A. simplicifolia which has simple leaves.

The species seem to be tolerant of sun or shade and will thrive in moist conditions near ponds or streams. About the only condition they do not tolerate well is hot, dry. Species and cultivars can vary in height from 8-12 inches up to 40 inches.

From the Greek for "without" and "brightness".