The variety of Asian greens available in the U.S. seems to increase almost daily, and each kind is liable to appear under numerous aliases. This guide is designed to help the would-be greens-eater find his or her way through this intriguing forest of exotic foliage—not only recognizing what's what, but learning which parts to use and how to use them.
BOK CHOY (Brassica rapa ssp. chinensis): Also known as pak choi or spoon cabbage. In most common types—white-stemmed, green-stemmed, and "soup spoon"—both leaves and stems are edible. Likewise the ever-more-common baby bok choy. One of the most delicately flavored Asian greens, bok choy is good for stir-frying (in oil, with garlic and soy sauce), braising, or simmering in soups.
CHINESE CABBAGE (Brassica rapa ssp. pekinensis): The two Chinese cabbages most common here: napa (nothing to do with the California valley), which is barrel-shaped, and michichili, more elongated. Both are mild and crunchy. Use them, thinly sliced and quickly cooked, as a bed for whole steamed fish or barbecued duck; simmer them in soup; or mix with meat as a filling for Chinese dumplings.
CHOY SUM (Brassica rapa var. parachinensis): Also known as yu choy; one type is called Chinese oil vegetable. The slightly bitter stems are more tender than the leaves, although all parts of the vegetable, even the tiny yellow flowers, are edible. Thick stems should be trimmed, peeled, then steamed or poached. Stir-fried, choy sum stands up well to the assertive flavors of garlic, rice wine, and chiles.
CHRYSANTHEMUM GREENS (Chrysanthemum coronarium): Often called garland chrysanthemums or crown daisies. Botanically different from other chrysanthemums. Leaves are flat or serrated. Tangy flavor. Becomes bitter if overcooked. Young leaves are quickly blanched to darken them, then coated with oil and added to salads. The Japanese use the leaves in tempura. The Chinese garnish soup with the petals.
MIZUNA (Brassica rapa ssp. nipposinica var. laciniata): Both the Japanese name, mizuna, and the Mandarin Chinese name, shui cai, mean "water vegetable" (the stalks are very juicy). Used frequently in Japanese cooking. The dark green, feathery leaves are peppery. Baby leaves are often used in field green mixtures; mature ones are excellent tossed with sauteed chicken or roasted root vegetables.
GREEN MUSTARD (Brassica juncea): Also called Chinese mustard greens and leaf mustard, this is among the most pungent of Asian greens. There are numerous sub-varieties, with leaves taking various shapes. Steamed for five minutes or so and dressed with a little oil, it makes a perfect side dish. Its flavor and texture work well with oyster sauce and with the richness of pork. It is also good pickled.
RED MUSTARD (Brassica juncea): More purple than red in color, this is one of the newer mustard varieties. Its powerful flavor, reminiscent of wasabi, fades if it's overcooked. Used more in Japanese and Korean cooking than in the Chinese kitchen. In the U.S., leaves can be served raw as a decorative, edible accompaniment to sushi, or added to soups just before serving (to preserve the leaf's character).
PEA SHOOTS (Pisum stivum): From the Leguminosae family. Correctly referred to as pea pod leaves, these are the tendrils and top few leaves of the snow pea plant. An important ingredient in Shanghai and Vietnamese cooking. Pinch leaves from stems, and use the tenderest tips. The delicate pea flavor comes through when they're used raw in salads, steamed, or stir-fried for a minute with a little ginger.
TATSOI (Brassica rapa var. rosularius or atrovirens): A ground-hugging member of the bok choy family, also known as rosette bok choy for its conformation: The round, thick, very dark green leaves grow in tight, concentric circles like rose petals. With its slightly bitter flavor, tatsoi is excellent raw (when young) in salads, and adds spark to Asian-style soups when tossed in at the last minute.