Plant Common Name
Broccoli, Cabbage, Cauliflower, Collards, Kale, Kohlrabi
Cabbage, kale, collard greens, broccoli, cauliflower, Brussels sprouts, kohlrabi, and other important green vegetables all descend from this short-lived perennial from coastal areas of western and southern Europe.
In the wild, Brassica oleracea forms dense over-wintering rosettes of large, fleshy, lobed, gray-green leaves, which give rise in spring to tall spikes of pale yellow, four-petaled flowers. Developed over many centuries, cultivated forms may have loose or densely packed rosettes of basal leaves (kale, collard greens, and cabbage) or stem leaves (Brussels sprouts), bulbous stems (kohlrabi), or large edible florets (broccoli and cauliflower). The foliage is typically thick, waxy, and deeply veined, and may be medium to dark green, green-gray, or purple-red in color. Plants may be annual or biennial. Hundreds of cultivars of varying sizes, shapes and colors exist and days to harvest vary widely depending on the cultivar.
Botanically, this diverse species is divided into the acephala group (kales, collards, and other loose-leaved vegetables); alboglabra group (annual Asian vegetables including Chinese broccoli and Chinese kale); botrytis group (cauliflower and broccoli); capitata group (cabbages); gemmifera group (Brussels sprouts); gongylodes group (kohlrabi); italica group (Italian broccoli types); and tronchunda group (Portugese cabbage and other cabbage-like annuals with spreading leaves).
These cool weather crops prefer full sun and fertile, organic-rich garden soil with ample drainage. Most are sown in the chill of early spring or in fall several weeks before first frost. In addition, many selections, including cabbages and kales, taste better if harvested after the first fall frost. These wonderful, variable vegetables are generally easy to grow and very tasty. Ornamental selections such as flowering kales are beautiful in fall gardens and containers.