Brassica rapa This close cousin of Bok Choy grows the most stunning rosette of elegant, dark green, spoon-shaped leaves on slender white stems. It’s easy to see why it has the nickname “spoon mustard” in some places. These greens have a delicate texture with a little crunch, and are excellent in salads, quickly wilted in a stir fry, or added to a soup at the end of cooking. Tatsoi needs full sun and well-drained soil. It can be direct-sown in spring, or late summer for fall harvest. It takes about 45 days to reach maturity.