Brassica oleracea, or Wild Cabbage, is a species of Brassica native to coastal southern and western Europe, where its tolerance of salt and lime and its intolerance of competition from other plants typically restrict its natural occurrence to limestone sea cliffs, like the chalk cliffs on both sides of the English Channel.
Wild Brassica oleracea 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 to 2 metres (3–7 ft) tall bearing numerous yellow flowers.
Although B. oleracea is believed to have been cultivated for several thousand years, its history as a domesticated plant is not clear before Greek and Roman times, when it is known to have been a well-established garden vegetable
It has become established as an important human food crop plant. According to the Triangle of U theory, B. oleracea is very closely related to five other species of the genus Brassica.
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.
You can find authentic Japanese Brassica Oleracea on many Japanese Restaurants in Los Angeles.