Specifically, it is a member of the sub-family called “brassica juncea”; the family that brown mustard seeds are harvested from. The plant could be grown and used for its brown mustard seeds, but it is cultivated primarily for its unique stem which can be cooked or pickled.
Its stem is a large, squat, knobbly bulb with large bumps on it. The stem will be about 4 to 6 inches (10 to 16 cm) tall, and about the same wide, weighing up to 1/2 pound (250 g.) There will be about 6 to 10 larges leaves on the plant. It prefers cool growing weather in the range of 46 to 56 F (8 to 13 C.) It is harvested for its stem after three months of growing.
The unpeeled stem is a light green colour.
The young leaves can be used as any other green in cooking, or shredded finely and added to salads.
Oil from the seed can be used as mustard flavouring.
The stem can be used in pickled items such as Szechuan Hot-Pickled Mustard Root, or in the Indian pickle known as “achar.”
The stem is generally peeled before use.