Strolling through the winter annuals at a local home improvement store, I saw the usual selection of pansies and violas, snapdragons and dianthus, plus my favorite holiday selections of Christmas cactus, poinsettia and cyclamen. What really caught my eye, however, was the display of ornamental cabbage and kale, Brassica oleracea. Although they are in the same genus of plants that includes cabbage, broccoli and cauliflower, these two members are better known for the color they add to the landscape rather than as tasty additions to the table. However, we can eat the foliage, raw or cooked, or use the leaves as garnish. Tastiness improves with the colder days; most folks say the foliage is just plain bitter. A concern of mine, if plants are purchased, is the potential for systemic pesticide residue from commercial production, so I have never eaten these ornamentals unless I have grown them from seed myself earlier in the fall.
The best time to plant these cool season ornamentals is now, when daytime temperatures will tend to stay below 75°. When temperatures remain too warm, plants stretch and become leggy. The color is noticeably missing. Good presentation of the white, pink and red pigments occurs after several frosts or prolonged cooler temperatures. If you have already made your purchases and plants have stretched, it is possible to dig them up carefully and nestle them deeper in the soil.
The growth differences between the two are noticeable. Ornamental cabbage looks very similar to edible cabbage in form, with a large head of ruffled leaves with smooth edges. Ornamental kale leaves are frilly edged, often deeply lobed and do not grow tightly folded together in a head. Plants are generally sold in various sized containers. The cell packs are always cheaper, but the root system is not as developed. I recommend investing in the larger 4-inch to 6-inch pots. Those grown in 1-gallon size pots are also available. No matter what size you choose, be sure the plants are not root-bound in the pot. They will have trouble increasing in size if this has occurred. Don’t hesitate to knock a plant carefully out of its pot to make a root inspection. I always do. Size increase is desirable so that a solid mass or border of color is achieved in the landscape. A good quality plant will have a very short or rosette type stem, leaves of even length, no visible damage from insects, a good root system and the beginnings of good leaf color. Remember color develops with cooler temperatures. When planting, be sure your site selection is in full sun, in a rich, moist, well-drained soil. With smaller plants, allow for a mature width of 10 inches to 12 inches. If starting with large plants, keep the spacing tight as they most likely won’t increase that much in width after planting.
Ornamental cabbage and kale have many uses in the winter garden. Planted in a border or in groupings of three, five or more plants, they make a spectacular display of both leaf color and texture. They are easily grown in window pots, containers, or directly in the garden. No pinching, pruning or staking is required. Few insects plague the plants as the temperatures get colder. Slugs, flea beetles, cabbage loopers and aphids that can be problematic all prefer warm temperatures.
Seed companies have developed a number of vigorous hybrids that easily tolerate temperatures in the mid to upper 20s. Innovations in color and form have helped make ornamental cabbage and kale a staple in many fall and winter gardens. The numerous color hues work beautifully with pansies, snapdragons and dianthus; the different sizes and shapes work in a variety of design situations. Some of the most popular varieties include Redbor, a narrow upright kale with deep purple ruffled leaves which can reach up to 3 feet in height. The Peacock series are large open plants that can reach 2 feet in width; the frilly leaves are deeply serrated, feather-like and come with cream or red-toned centers. Pigeon series grow to resemble garden cabbage with tight round rosettes, but the rosettes are light pink, dark red or creamy white. The outer leaves are wavy and remain mostly green. Osaka series are also good choices, and offer a more structured form with smooth, flat leaves and wavy edges. Rosettes are tightly compact heads that gradually turn bright purple, pink or cream while outer leaves remain green.
If you have never experimented with ornamental cabbage and kale, they are worth a try. There has been so much unwanted change in 2020, maybe one change over which you actually have control will feel good!