Paeonia rockii

Rock's Peony (botanical name, Paeonia rockii) is a woody species of the peony, named after Vienna-born American Joseph Rock.

This tree peony species is very frost hardy and resistant to fungal diseases, so it can grow and flower in Europe, particularly in northern countries, such as Sweden or Finland. In Germany it is the most hardy tree peony species.

Rockii-hybrids

Tree peony hybrids including Paeonia rockii as one parent are called Rockii-hybrids. In China there is a cultivar group out of these hybrids, called Gansu mudan, or North-West Chinese cultivar group.