The plants grow very fast; the leaves are usually ready to pick about 30 days after planting seed. The deep green leaves from brown mustard plants are about 6 inches long (15 cm) with rough edges. They have a very sharp mustardy taste, though occasionally the leaves from a plant will be milder.
You can get them fresh, frozen or canned. When buying fresh, choose crisp leaves with deep colour and with no yellowing or bug holes.
European varieties include Elephant Ear (large, flat leaves), Fordhook Fancy (curly leaves), Green Wave (very curly leaves), Florida Broadleaf (flat leaves, therefore easier to wash), and Southern Giant Curled (crumpled, curly leaves.)
Asian varieties include Green-in-Snow, Osaka Purple-Leaved and Red Giant.
In France, the brown mustard plant is grown not just for its leaves, but also for the seeds to make whole grain mustards. Varieties grown include Burgonde, French Brown and Tilney.
Wash the leaves well. Discard the stems, except on very young leaves. Very young leaves can be used fresh in salad. Older leaves need to be cooked. Allow the same cooking time as for spinach leaves, about 3 minutes braising or steaming.
Avoid cooking in cast iron or aluminum.
Many seasoned Mustard Green hands will mix Mustard Greens with other greens, so that their sharpness accents rather than overwhelms.
Store in fridge in plastic bag for up to 2 days. Freezing: Wash, remove stems. Blanch (not steaming) for 2 minutes. Plunge in cold water, drain, package, and freeze.
Native to Asia, hybrid between something in the turnip family and black mustard plants.