Paeonia ostii is a hardy shrub in the peony family, Paeoniaceae.

It can be found in the Gansu, Anhui, Shaanxi and Henan provinces of China.

It can reach heights of 1.5 m, and has grey-brown bark and lance-shaped leaflets.

Flowers are produced in mid-spring, measure up to 15 cm across, and are typically pure white without basal blotches.

It grows in deciduous forests, and on slopes to an altitude of 300-600 m.[2] This species is the parent of two medicinal varieties of tree peonies.