615 Brassica oleracea var. acephalaCommon Names: kale, collards, flowering cabbage, cole Family: Brassicaceae (cabbage Family)
Kale and collards are biennials and perennials, usually grown as annuals for their edible leaves which do not form dense heads like cabbage. Collards have thick, fleshy, smooth leaves up to 2 ft (0.6 m) long and a 1.5 ft (0.5 m) wide. They have smooth margins and look like the outer or basal, non-heading leaves of cabbage. The lower leaves tend to sag down and the upper ones are more erect and cup-shaped. Kale leaves are not as thick as collards and in many cultivars they are fringed or wavy-edged. Kale plants, and their leaves, are smaller than those of collards. There are many cultivars of kale and collards. Some were selected more for ornamental use than food. My favorite kale for raw eating in salads is 'Vates Dwarf Blue Curled', and my favorite collard greens for cooking is 'Georgia Southern'. 'Tuscan' and 'Lacinato' are primitive kales with very dark green, narrow, upright, savoyed (crimped) leaves that are as ornamental as they are tasty. 'Morris Heading' is a collard that produces a loose head, somewhat like cabbage, but higher up on the stem. 'Walking Stick' kale is grown in the (English) Channel Islands for the tall, straight stem which is dried, polished and made into handsome walking sticks.
The various cultivars of ornamental kale have feathery, fringed leaves, and the ones called "ornamental cabbage" have rounded leaves. These are as good in the cookpot as they are in the winter flower bed. The very kale-like Siberian kale (a.k.a. Hanover salad) is not a kale at all, but rather a member of the Brassica napus species, which includes also rutabaga, canola and rape.
The original wild cabbage (Brassica oleracea ssp. oleracea) from which kale, collards, cabbage, broccoli, cauliflower, and other crops were developed, still grows along the coasts of north Africa and Europe. Kale and collards probably were the first brassicas (probably the first plants!) to be cultivated, and they are quite similar to the wild cabbage that still persists.
CultureKale and collards are the easiest of the brassicas to grow. You can begin harvesting leaves 30 days after planting. Light: Both kale and collards grow best in full sunlight. In the heat of summer, though, they appreciate some shade, and it could make the difference between surviving the summer and joining the compost. Moisture: Regular watering is best for good growth. Collards are more drought tolerant than other brassicas. Hardiness: USDA Zones 3 - 10. Kale and collards can take freezing temperatures down to at least 20º F (-6.7º C). It only makes them sweeter! It's heat that puts the damper on these two cool weather vegetables. Collards are the most heat-tolerant of the brassicas. They usually can survive the hot summers of the southern US. But kale, like cabbage, broccoli, and cauliflower, peters out when temperatures start getting above 80º F (26.7º C) on a regular basis. In north Florida, we plant kale and collards in September or October and harvest leaves as needed from November through April. Propagation: Kale and collards are grown from seeds which germinate in 3-7 days.
Harvest outer leaves from kale and collard plants for cooking as you need them. Collard leaves harvested in warm weather can be sweetened by storing in the refrigerator for a couple days before cooking. Collard plants in the kitchen garden that have survived a year or more often look like miniature palm trees or tree ferns, with a thick, 3 ft (0.9 m) stem devoid of leaves along most its length, and a dense tuft of spreading leaves at the top. Southerners traditionally boil collards with some salt pork or ham, but too much cooking destroys their considerable nutritious value. Collards and kale have a milder, less tangy taste than mustard greens or turnip greens, and I like to mix them together and steam briefly in a vegetable steamer. Remove the thick stems and midribs for a smoother texture. A little butter and some salt and pepper is all they need, but vinegar is nice too.
Use the young, frilly leaves of kale fresh in salads.
Kale and collards are members of the same species as cabbage, Brussels sprouts, kohlrabi, broccoli and cauliflower. See Floridata's cabbage (Brassica oleracea var. capitata) profile for a discussion of the amazing diversity within Brassica oleracea.
All members of the genus Brassica contain very high levels of antioxidant and anticancer compounds. Some authorities say that kale has the highest concentrations of all. Some of these compounds enhance antioxidant and detoxification effects in the body. Others inhibit tumor growth; some block cancer causing compounds, and some prevent the formation of carcinogens. The American Cancer Society recommends that Americans increase their intake of kale, cabbage, and other brassicas. It has also been reported that compounds in brassicas can protect the eyes against macular degeneration. So, eat those greens!
Steve Christman 1/11/00; updated 5/10/03, 9/5/03, 12/29/07