cabbage, broccoli, and allies

Wild Brassica oleracea is a tall biennial or perennial plant that forms a stout rosette of large leaves in its first year. The grayish-green leaves are fleshy and thick, helping the plant store water and nutrients in difficult environments. In its second year, a woody spike grows up to 1.5 metres (5 ft) tall, from which branch off stems with long clusters of four-petaled yellow flowers.

Wild cabbage is considered to be native only to the coasts of France, Great Britain, and Spain, although widely naturalized elsewhere. Although rarely abundant, wild cabbage is also found on the coasts of Ireland, Italy, and the German island of Heligoland. Wild cabbage is a hardy plant with high tolerance for salt and lime. Its intolerance of competition from other plants typically restricts its natural occurrence to limestone sea cliffs, like the chalk cliffs on both sides of the English Channel.

The species has become established as an important human food crop, used because of its large food reserves, which are stored over the winter in its leaves. It has been bred into a wide range of cultivars, including cabbage, broccoli, cauliflower, brussels sprouts, collards, and kale, some of which are hardly recognizable as being members of the same genus, let alone species. The historical genus of Crucifera, meaning "cross-bearing" in reference to the four-petaled flowers, may be the only unifying feature beyond taste. The plant is tolerant of a variety of soil conditions between pH 6.0 and 7.5, but grows particularly well in alkaline soils in full sunlight, with good drainage and high amounts of nitrogen. The plant can grow in partial shade, but care must be taken to provide sufficient ventilation, as this reduces the prevalence of downy mildew.

History. Researchers believe that B. oleracea has been cultivated for several thousand years, but its history as a domesticated plant is not clear before Greek and Roman times, when it was a well-established garden vegetable. Theophrastus mentions three kinds of rhaphanos (ῥάφανος): a curly-leaved, a smooth-leaved, and a wild-type. …

"Brassica" was Pliny the Elder's name for several cabbage-like plants. Its specific epithet oleracea means 'vegetable/herbal' in Latin and is a form of holeraceus (oleraceus).