Gansu zhongchuan peony nursery have selected nearly 600 varieties rockii tree peony through the seedling breeding and cross breeding . According to their colors ,we can divide them into eight types such as white peony, yellow peony, pink peony, red peony, purple peony, blue peony, black peony and multi-color peony(one flower with two colors) , the following we introduce some part of it.
（一）the white system
Most of wild rockii peony are white, single type.And they are still white,but less petal after hybridization. A variety of stains in petals’ base make wild rockii special. This type of peony plants have strong adaptability and high growth rate .
2、Semidouble type:White Crane Spreading Wings
3、Double type: Long Ice Road
（二）Light yellow flower system
Rockii tree peony cultivars lack of pure yellow. Pale yellow flowers generally refers to that the original flower petals are yellowish, flower petals are white after blooming .
3、Double type: Yellow Cloud
（三）Pink flower system
Paeonia rockii hybrids with Chinese peony, most of their filial generation are pink varieties. Pink refers to the uniform light red or pale pink. This type are strong stress resistance and middle growth potential .
3、Double type:Snowy Twilight
（四）Red flower system
These flowers are mainly brightly red color , other colors are brown, orange and blue. Grow commonly.
3、Double type: Red Crown & Jade Bead
（五）Purple flower system
Purple is a color between red and black. Generaly this type of plants' potentiality of growth is weak, the part of the varieties are not resistant to sunlight.
1、sigle type: Purple Lotus
3、Double type: Silver Waves of Purple Sea
六）Blue flower system
The color of blue rockii peony are similar to lilac’s color. This variety grows strongly. It is a easy divided and breeding plant.
（七）Black flower system
Black refers to deep purple appear black halo, in the shade this condition are more obvious. This type of plant's potentiality of growth is weak, and it is hard to breed.
1、sigle type: Luminous Jade Cup
2、Double type: Black Crown & Jade Wings
（八）multi- color flower system
Multi-color flower refers to a flower has two or more colors, with different form combination. This kind of flower's adaptability is strong and grow strongly.