45 Days to maturity. Brassica rapa Japonica group. Early Mizuna Mustard Seeds. Heirloom, Non-GMO, Open Pollinated. Annual. This early maturing Japanese mustard is also known as Kyona Mizuna. The mustard variety name, kyona mizuna, originated in the Kyoto area and is a type commonly grown in this region. Ours was selected from this type and is considered a Kyoto or Kyona type. It has long slender stems and dark green serrated leaves. This mustard variety is tolerant to both heat and cold. It is slow to bolt and is it is a vigorous dark green, that produces multiple branches that can be easily harvested. Approx 13,000 seeds / oz.