The Chinese peony is a herbaceous perennial. It has erect stems with lobed leaves and very large, scented flowers, which in the wild are white and single. Cultivated plants grow to 1m, are full hardy and can be red, pink or purple and are usually double.
photograph sourced from Wikipedia
The tree peony found from Western China to Bhutan forms a branched upright shrub to 2m with slash cut and lobed leaves. The terminal flowers are very large and slightly fragrant. Common peony is a herbaceous perennial with many erect stems to 75cm, bipinnate leaves composed of ovate-lanceolate segments and large terminal flowers that are single, fragrant, usually purple-crimson and hermaphroditic.
Peonies prefer cold winters and a deep, rich, moist soil. Plant fresh seed in autumn or stratify older seed, then plant in spring. You can also divide plants in late autumn or spring, take root cuttings in winter or semi-ripe stem cuttings. Peonies require heavy feeding and their roots resent disturbance. Remove dead wood in spring.
The flowers of P.officinalis are used to scent tea, and the seeds were once used as a spice.
Information sourced from The Complete Book of Herbs