Probably of Japanese origin, n-mitsuba, meaning 3 leaflets is cultivated in Japan, Korea, and China. Like celery but a much smaller plant, it is grown for its long slender petioles and leaflets. The petioles are 10 to 15 cm long and 2 to 4 mm in thickness. When blanched or grown under crowded conditions, the petioles elongate to 30 cm or more in length. In Japan, mitsuba is grown all year round in plastic houses, with the main production from fall through winter.
Some growers culture the crop on polyfoam blocks which are floated on nutrient solution.
Mitsuba is grown commercially near Los Angeles, California, in plastic houses for the oriental people in that area. Raphanus sativas L., cultivar 'Sing li mei'. In 1979, while visiting an agricultural experiment station in Japan, I saw some red flesh winter radish grown from seed brought from mainland China. While in China this summer, I saw this radish again. It was developed by a breeder at the Beijing Vegetable Research Center.