Ornamental cabbage is a varietal of cabbage which is grown for its colorful, showy leaves. It is also sometimes known as ornamental or flowering kale. Just like table cabbage, Brussels sprouts, broccoli, kale, cauliflower, and kohlrabi, ornamental cabbage is classified as Brassica oleracea, and it has acquired a distinctive look through years of assiduous cultivation. It is also technically edible, although it can get extremely bitter and the leaves tend to turn a dull gray when they are cooked.
There are a number of varieties of ornamental cabbage. As a general rule, the plants have tight, well rounded heads and ruffly foliage. Their colors range from white to red, with tones of pink, purple, and green in many varietals and ornamental cabbage is often striped with rich streaks of color. When it is well tended, the plant can be used to make a splash of color in the garden, and it can also line beds, walkways, and paths.
One of the primary advantages of ornamental cabbage is that it is a cool weather plant, preferring the temperatures of fall and winter. When other plants in the garden may be dormant or dying off, ornamental cabbage can be bright and vibrant. If you live in an area which only gets light frosts during the year, ornamental cabbage can persist through the winter, providing a bright note during dark, cold months. The plant can also be grown indoors, if you have a cool, brightly lit room.
All ornamental cabbages are grown from seed. If you want to start your own plants, you can buy seeds from a local gardening store; the seed package will usually have a photograph illustrating the color and form of that particular variety of ornamental cabbage. Plant the seeds in July or August, either directly in the ground or indoors in pots if your summers are hot. Keep the soil moist and well amended with compost, and weed out straggly plants as the ornamental cabbage grows. If you start plants indoors, move them out in the mid fall so that they have time to acclimatize to cooler temperatures. A light frost will actually make the color more saturated and intense, but you don't want to shock the plants by planting them in the late fall, when temperatures are dramatically cooler than they are indoors.
You can also buy ornamental cabbage seedlings in packs. If you get seedlings, choose the strongest looking, most symmetrical plants, and set them out in the garden in the mid fall. As the ornamental cabbage grows, you may want to trim trailing leaves to keep the plants tidy. The plants will go to seed in warmer weather; if you like the varietal you are growing, save the seeds to plant in the late summer.