648 Brassica napusCommon Names: rutabaga, Swedish turnip, canola, rape Family: Brassicaceae (cabbage Family)
Brassica napus is a variable species, divided into three groups or subspecies: B. n. napobrassica includes the rutabagas (a.k.a. Swedes in England), grown for their enlarged turnip-like swollen stems; B. n. pabularia includes Siberian kale and Hanover salad, grown for leafy kale-like greens; and B. n. oleifera includes rape and canola, (colza in India) grown for edible leaves, as forage crops for livestock, or for the seeds from which vegetable oil is made. All have large, flat leaves 12-20 in (30.5-50.8 cm) long and 8-15 in (20.3-38.1 cm) wide; all stand 2-4 ft (0.6-1.2 m) tall at most; all have yellow, cross-shaped flowers with four petals; and all produce sickle shaped pods containing tiny round seeds.
Rutabagas are like turnips except that the flesh of the edible root (swollen stem) is a little less watery, a little milder, and usually yellow, although there are some white fleshed varieties (e.g., 'Merrick'). The leaves are bluish-green and smooth, unlike turnip leaves which are light green and hairy. Siberian kale is very much like true kale, and the seed is often sold in garden centers simply as "kale." It is more heat tolerant and more cold tolerant than true kale, grows a little larger, and tastes just as good. Rape is generally grown in large fields for animal fodder or rapeseed oil (a.k.a. colza oil in Asia). Canola is a new type of rape grown commercially for the seed, which is lower in saturated fats and fatty acids than the original rapeseed.
It is believed that Brassica napus originated from a fortuitous hybridization between the turnip (B. rapa) and kale (B. oleracea acephala), probably in European gardens during the Middle Ages. Canola, a selected genetic variant of rape, was developed in the late 1970's in Manitoba, Canada, as a more nutritious source of vegetable oil than rapeseed.
CultureRutabagas require about 90 days to reach harvestable size. Individual leaves of Siberian kale can be picked beginning about 30 days after planting. Light: All of the B. napus varieties should have full sun for maximum performance. Moisture: Regular garden watering. Hardiness: USDA Zones 3 - 10. Rutabagas are hardier than turnips, easily tolerating temperatures down to 15ºF (-9.4ºC). Siberian kale, rape and canola also are hardy to temperatures in the mid to low twenties. In the South, all B. napus varieties are grown in the winter. In the north, early spring plantings produce crops before summer heat causes them to bolt to flower. The flavor of rutabaga and of Siberian kale is enhanced by frost. Propagation: Seeds are sown in place. Plant rutabaga 4-6 in (10.2-15.2 cm) apart in rows 30 in (76.2 cm) apart. Siberian kale can be planted closer together or in wide rows like spinach or kale. Canola seed is either broadcast at 20 pounds (9 kg) per acre, or planted in rows 28 in (71 cm) apart at four pounds (1.8 kg) per acre.
Rutabagas are common table fare in northern Europe. They can be baked, mashed, fried, added to soups and stews, or eaten raw. Scandinavians brush rutabagas with oil and bake until tender, then cut them open and insert some cheese before serving. Fresh from the garden, raw rutabaga, with a little salt, is an excellent snack, similar to kohlrabi or radish. Siberian kale is an excellent pot herb, cooked like spinach in a little water, or just steamed over boiling water. I can't taste any difference between Siberian kale and true kale, but some say Siberian kale is better tasting.
Canola is grown commercially in Canada and some parts of the US. Scientists at the University of Florida are currently field-testing canola as a potential winter crop in the South. Theoretically, a field of canola could be planted and harvested between October and April, on the same ground that a summer crop such as peanuts or cotton is grown. Several cultivars of rape, especially 'Dwarf Essex', are grown for livestock forage in Europe, Australia and North America.
All of the crucifers (or brassicas, or cole crops) are high in antioxidant and anticancer compounds. The anti-cancer properties of these vegetables are so well established that the American Cancer Society recommends that Americans increase their intake of cruciferous vegetables. Other research has suggested that the compounds in brassicas can protect the eyes against macular degeneration, the leading cause of blindness in older people. See Floridata's mustard greens (B. juncea) profile for a partial listing of the edible Brassica species. For everything you always wanted to know about canola, see the Canadian site: http://www.canola-council.org/.
Steve Christman 3/19/00; updated 11/15/03