Flowering kale and cabbage are favorite cool-season plants, but I recently saw them from a new perspective – backlit by the late afternoon sun. I was amazed at the brilliant purples and mauves in some leaves and iridescent stripes in others.
We think of kale and cabbage as pansy partners or to be used in stunning combinations with snapdragons, but after watching them closely throughout the day I believe they can offer all the cool-season sizzle you may want.
These plants, which survive in zones just about anywhere in as cold as zero degrees, are among the easiest to grow. They do prefer fertile, well-drained soil. At the Columbus Botanical Garden, we added a 4-inch layer of organic matter prior to rototilling. We also incorporated a slow-release, 12-6-6-fertilizer at a rate of 2 pounds per 100 square feet of bed space.
Flowering kale and cabbage should be set in the soil to a depth just slightly below the bottom set of leaves. The plants will reach 6 to 12 inches in height, and you will want to space them 12 to 18 inches apart. Even though we are approaching mid-November, garden centers are loaded with good supplies and a number of varieties.
After planting, add a good layer of mulch to help stabilize soil temperatures and conserve moisture. We used pine straw but there is nothing prettier than fresh bark mulch. One nice note on pine straw: You can completely cover the kale should record cold be forecast, and leave it covered for a few days until the temperature moderates.
Kale and cabbage need good drainage, yet must be kept moist and fed to keep them growing vigorously. Pay close attention, because dry, cold fronts have a tendency to deplete the available moisture. Feed with a diluted water-soluble fertilizer every four to six weeks. The colors intensify as the temperatures get cold. I can see a dramatic change after temperatures in the high 30s.
Unfortunately, the same cabbageworms that attack broccoli can be a pest on these plants. Watch and treat as needed with Bacillus thuringensis. This organic pest control poses no threat to gardeners.
These plants can be showy by themselves, or for a riveting display, try bold drifts of pink or purple kale next to another drift of a white variety. Consider planting a large bed of narcissus behind the kale or cabbage for special spring crescendo.
Kale and cabbage also are exceptional in large containers, where you might place three in a triangular design. Plant tulips or daffodils in the center of the triangle and then place pansies around the edges.
There are many more varieties than gardeners realize. The Chidori series with its fringed ruffled leaves and intense colors have become popular. The Peacock and Sparrow series also have to be considered among the prettiest.