Brassica juncea, also known as mustard greens, Indian mustard, Chinese mustard, and leaf mustard, is a species of mustard plant. Subvarieties include southern giant curled mustard, which resembles a headless cabbage such as kale, but with a distinct horseradish-mustard flavor. It is also known as green mustard cabbage.
The leaves, the seeds, and the stem of this mustard variety are edible. The plant appears in some form in African, Italian, Indian, Chinese, Japanese, and soul food cuisine.
Vegetable growers sometimes grow mustard as a green manure. Its main purpose is to act as a mulch, covering the soil to suppress weeds between crops. If grown as a green manure, the mustard plants are cut down at the base when sufficiently grown, and left to wither on the surface, continuing to act as a mulch until the next crop is due for sowing, when the mustard is dug in. In the UK, summer and autumn-sown mustard is cut down from October. April sowings can be cut down in June, keeping the ground clear for summer-sown crops.