pinach Mustard Komatsuna Greens Brassica Rapa Vegetable Seeds. 45 days. Mustard-Spinach or Komatsuna. Milder than regular mustard greens, this variety has thick, smooth leaves on upright, heat and cold tolerant plants. Tendergreen is widely used both in stir fry and in salads. Its tender leaves, as well as its flowering stems, are used raw or are cooked and have a flavor between mustard greens and cabbage.