Brassica oleracea or Wild Mustard, is a species of Brassica native to coastal southern and western Europe, where its tolerance of salt and lime but intolerance of competition from other plants typically restricts its natural occurrence to limestone sea cliffs.
Wild B. olearacea is a tall biennial plant, forming a stout rosette of large leaves in the first year, the leaves being fleshier and thicker than those of other species of Brassica, adaptations to store water and nutrients in its difficult growing environment. In its second year, the stored nutrients are used to produce a flower spike 1–2 m tall bearing numerous yellow flowers.
The plant is used because of its large food reserves, which are stored over the winter in its leaves. It is rich in essential nutrients including vitamin C.
The cultivars of B. oleracea are grouped by developmental form into seven major cultivar groups, of which the Acephala Group remains most like the natural Wild Cabbage in appearance:
For other edible plants in the family Brassicaceae, see cruciferous vegetables.