Paeonia

The common or European peony: a compact herbaceous perennial of rocky woods, scrub and mountain meadows in southern Europe, with divided leaves and single, mildly fragrant crimson flowers in May. Grown for centuries as a medicinal plant before it became an ornamental, it dies back to the ground every autumn and lives for decades if left undisturbed. All parts are poisonous in large doses.

The classic common garden (or Chinese) peony - an erect, clump-forming herbaceous perennial native to China, Tibet, and Siberia that rises 18 to 30 inches on red-tinged stems clothed in glossy, deeply divided dark-green leaves. In May it opens large, cup-to-bowl-shaped flowers of white, pink, or crimson around a conspicuous boss of yellow stamens; most cultivars are fragrant and superb for cutting. Long-lived and undemanding, a single planting needs a cold winter to bloom and can be left undisturbed for decades.

The tree peony, or moutan: a slow, long-lived deciduous shrub bred in Chinese gardens for well over a thousand years for its huge spring flowers, up to 8 inches across, in white, pink, red, purple and, in some hybrids, yellow. Unlike the herbaceous peonies it keeps its woody stems through winter and is never cut to the ground. The name covers a cultivated hybrid complex rather than a wild species.