P. rockii is known for the obvious black, purple, and brown-red spots at the base of petals. Its main features are:
1. Tall plant, can reach 2-3 m high, crown width 3-4 m.
2. Big and bright flower, the diameter can reach 18-25 cm.
3. Strong fragrance; the smell of one open flower can dominate that of 10 other open flowers from another peony.
4. Resistance to drought and frost; tolerance of salt and base. Can bear temperatures as low as -43°C; can still grow normally at pH above 7.
5. Distinct Purple/black spots at the base of the petals.
The cultivation of Paeonia rockii is simple and does not require strict management; it is less attacked by diseases and pests, but in hot and humid weather leaves will grow mould and present scorched leaf symptoms; a sterilizing can be sprayed on foliage to combat the disease.
The planting seasons are fall and spring.
There are 3 ways of propagation: sowing, budding, and grafting.
Sown seeds can blossom after five years; grafted and budded seedlings can blossom just after plantation, but need 2-3 years after the rejuvenation period to offer a better blossom.
The difference between Paeonia rockii and Chinese tree peony (P. suffruticosa)
Paeonia rockii is one of the most important members of Chinese peony family.
A research revealed that, Paeonia rockii comes after the Chinese tree peonies cultivars stock including Heze in Shandong and Luoyang in Henan, as China’s second largest cultivated peony varieties group.
Its main features are cold hardiness, drought tolerance, tall plants, big and bright flowers, strong fragrance, strong resistance to diseases and pests, and wide adaptability; it can especially be open to winter at minus 43°C without any artificial measures of protection, and is appropriate for cultivation in cold regions.
As for the world famous Chinese tree peony in Luoyang and Heze, the plant height does not generally exceed 1.5 meters, but the height of Paeonia rockii can usually reach over 3 meters; the higher the tree, the more flowers, and the biggest tree can produce four to five hundreds of flowers; Paeonia rockii blossom is therefore natural and poised, and offers a magnificent spectacle.