The peony or paeony is any flowering plant in the genus Paeonia, the only genus in the family Paeoniaceae. Peonies are native to Asia, Europe, and Western North America. Scientists differ on the number of species that can be distinguished, ranging from 25 to 40, although the current consensus describes 33 known species. The relationships between the species need to be further clarified.

Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials.