What is the difference between Japanese and Chinese tree peonies?

Many Japanese tree peonies are Chinese tree peonies with Japanese names. The garden tree peony was brought to Japan from China at the beginning of the 17th century. The Japanese, in an aesthetic decision, chose to grow plants that have single or semi-double flowers, grow 4 to 6 ft. high, and (with some notable exceptions), have little or no fragrance. Chinese tree peonies range in form from single to complex double shapes, and many cultivars are fragrant.