Zi Yan (Purple Pink Ink Stone). Chen Dezhong. Unregistered with the APS. P. rockii influence hybrid. Gansu-mudan. A large dark purple-red single to double flower. Rockii lineage is evident in its long leaves and small leaflets. Grows to about 4 feet high by 6+ feet wide in Wisconsin. Extremely hardy winter stems. Flowers are carried on long stems and nod in the breeze. Some years it blooms single with large black flares visible, other years it is a full double. Excellent plant for the northern climate. Slow growing initially. Gansu-mudan are Chinese rockii lineage hybrids. Recommended for cold winter climates. Ships late September to mid October.