Flowering cabbage (Brassica oleraceais) is a popular fall ornamental. Late fall flowering cabbage can easily withstand several hard frosts. It is not uncommon for the plants to maintain their flowering ability into the first weeks of December even in a harsh winter climate. Each frost greatly intensifies the cabbage's color which adds to its appeal in the garden setting. Flowering cabbage can also be successfully grown indoors as a container plant in a cool house setting.
Cabbage or Kale?
Flowering cabbage and flowering kale are often hard to tell apart. The flowering cabbage plants have a smooth leaf margin but the flowering kale leaves appear to be fringed on the leaf margins. Some kale varieties also have a ruffled leaf margin that stands out.
Flowering cabbage leaves contain chlorophyll. When chlorophyll is exposed to nighttime temperatures that dip below 50 degrees F the coloration of the leaves gradually begins to change. Colors will begin white and change to pink and often settle on a deep brilliant red. With each successive cold night the change becomes more and more subtle. The complete color metamorphosis usually takes up to four weeks of cold weather to achieve.
Seeds and Growth
Cabbage plant seeds need to be sown in June in to achieve enough growth for fall planting. The plants take about two-and-a-half months to grow to a marketable size. In a southern location the seeds can sometimes be successfully sown in July. Seedlings should be planted in 6-inch pots to allow enough growth to take place before the fall outdoor planting. Growing flowering cabbage from seed is difficult and requires a greenhouse setting where the temperatures can be controlled, according to the University of Wisconsin. In cool climates, seeds can be sown outdoors if temperature requirements remain ideal.
Ornamental flowering cabbage is edible but it does contain a more bitter taste than common cabbage varieties. The leaves are often used for decorative purposes in food and on plates by chefs around the world. The bright colors of flowering cabbage disappear when the plant is cooked and it simply looks like common cabbage.
Flowering cabbage does not normally suffer from severe pests, unlike regular cabbage, because of its late season growth. The plants can often be bothered by cabbage looper, leaf roller and aphids, but the cold weather normally kills off the pests.