Bok choy, also known as Chinese cabbage, is a cool-season biennial vegetable that is normally harvested for consumption in its first year of growth. It has crisp stalks surrounded by smooth, tender leaves with a flavor that is somewhere between cabbage and chard. Plants form an upright head, with outward flaring leaves, and its white or green stalks look like smooth, non-stringy celery. The stalk can shoot up to twice the size of the plant. Flower stalks grow from the center of the plant and have the yellow, four-petal cross typical of the cruciferous family.Bok choy is a type of Chinese cabbage that once was limited to meals in Chinese restaurants. These days, however, you are just as likely to find it growing in backyard gardens. There are a surprising number of varieties to try. Its Chinese name, "pak choi," translates to "white cabbage," probably because of its blanched centers, but there are green varieties too. Plant size varies depending on variety— some are less than 10 inches tall, but standard varieties grow 1 to 2 feet tall, with a spread of about 12 inches.