Mizuna (Japanese: ‘water greens’), also called Xiu Cai, Kyona, Japanese Mustard, Potherb Mustard, Japanese Greens, California Peppergrass, Spider Mustard, etc., is a Japanese name used primarily for cultivated varieties of Brassica rapa nipposinica but also for Brassica juncea var. japonica.
The taste of mizuna has been described as a “piquant, mild peppery flavor…slightly spicy, but less so than arugula.” It is also used in stir-fries, soups, and nabemono.
In addition to the term “mizuna” (and its alternates) being applied to at least two different species of Brassica, horticulturalists have defined and named a number of varieties. For example, a resource provided by Cornell University and the United States Department of Agriculture lists sixteen varieties including “Early Mizuna”, “Kyona Mizuna”, “Komatsuna Mizuna”, “Vitamin Green Mizuna”, “Kyoto Mizuna”, “Happy Rich Mizuna”, “Summer Fest Mizuna”, “Tokyo Early Mizuna”, “Mibuna Mizuna”, “Red Komatsuna Mizuna”, “Waido Mizuna” and “Purple Mizuna”.
Mizuna has been cultivated in Japan since ancient times, but most likely originated in China.