Brassica oleracea var. palmifolia Seeds | Black Kale
LATIN NAME: Brassica oleracea var. Palmifolia
COMMON NAME: Black Kale, Cavolo Nero, Tuscan Kale
Plant Profile
Black Kale, cavolo nero, is a non-heading cabbage grown in Tuscany for centuries, forming an upright rosette of long, narrow, deeply blistered leaves of an intense blue-black-green. The leaves are tough and strongly savoyed, with a sweet, mineral flavour that improves after frost, and the plant can be harvested leaf by leaf through winter.
It is one of the oldest kales still in cultivation and the classic leaf of ribollita, minestrone and Tuscan bean soups. It is a variety of Brassica oleracea, the same species as cabbage, broccoli and cauliflower, and it grows on a single stem that can reach a metre in a long season.
Science & Biotechnology
The dark colour comes from a high concentration of chlorophyll and anthocyanins, and the leaves are correspondingly rich in carotenoids, vitamin K and glucosinolates. Glucosinolates break down on chewing into isothiocyanates, including sulforaphane, and black kale is one of the brassicas most often used in studies of those compounds.
Breeding work on the variety has concentrated on uniformity, cold tolerance and resistance to downy mildew, which can strip the leaves in a wet autumn. Seed saved from garden plants will produce variable offspring, since B. oleracea outcrosses freely with other brassicas flowering nearby. In trials, black kale is consistently among the highest-yielding winter brassicas for leaf production, and it suffers less from pigeons than ordinary cabbage.
Uses & Benefits
The leaves are eaten cooked: blanched, then braised with oil and garlic, or added to soups and stews where their firm texture holds up to long cooking. Young leaves can be eaten raw in salads, and the stems, peeled, are cooked like broccoli.
It has become a fashionable crop well beyond Tuscany, grown for its appearance as much as its flavour, and it is a useful winter vegetable in a cold climate because it stands through frost. In the garden it is ornamental enough for a mixed border, with its arching blue leaves. The stems are woody and usually discarded, though in Tuscany they go into the soup pot for the flavour they give.
Growing from Seed
Sow in late spring or early summer, one centimetre deep in a firm seed compost, at 18 to 20 °C. Germination is quick, usually within a week, and the seedlings grow fast enough to be planted out in five or six weeks.
Set the plants out 45 cm apart in firm, fertile soil in full sun, and water well until they are established. Stake the tall stems in exposed gardens, and pick the lower leaves first, leaving the crown to keep producing. A late sowing gives tender leaves in autumn; a midsummer sowing gives a plant that stands through winter and tastes sweeter after frost. Net the plants against pigeons in winter, and earth up the stems slightly to keep them steady in wind.
Our Take
The best-tasting kale for winter, and one of the oldest in cultivation. It wants firm soil, full sun and cold weather to sweeten it, and gives leaf after leaf from one sowing.
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