Brassica rapa var. chinensis. Jade Spring choi sum seeds produce a short season, fast-growing hybrid variety of Yu Tsai Sum (or Choi Sum) that produces raw stems with the texture of lightly steamed asparagus, with a sweet, mild taste. Stems will be 5mm - 1cm thick if grown and watered well. Early spring plantings may bolt. The incredible flavour will have you eating it raw, straight out of the garden, before it can be cut for stir-fries, salads, or soups. The plants in our trials have been consistently uniform and show few signs of damage from pests or disease.