Brassica oleracea (Ornamental cabbage and kale)

Article by Extension Master Gardener℠ volunteer Kathryn Copley

White and purple ornamental kale plants; Terren; CC BY 2.0

Ornamental cabbage and kale are great for replacing worn-out summer annuals for a long-lasting fall display of large rosettes of white, pink, purple or red leaves. Ornamental cabbage and kale (also known as “flowering” cabbage and kale) are in the same species (Brassica oleracea) as edible cabbage, broccoli, and cauli-flower, but cultivars with colored leaves are considered ornamental rather than edible.

Brassica oleracea flowering kale; Mypouss; CC BY 2.0

Technically, ornamental cabbage and kale are all kales (kales produce leaves in a tight rosette; cabbages produce heads). But in the horticultural trade, ornamental kale is the term used for types with deeply-cut, curly, frilly or ruffled leaves. Ornamental cabbage is the term used for types with broad, flat leaves that are edged in a contrasting color.

Some ornamental varieties of cabbage / kale are:

• ‘Coral Prince’ — creamy white center surrounded by feathery green leaves
• ‘Coral Queen’ — deep red center surrounded by green leaves
• ‘Nagoya’ — red, white or rose center with fringed purplish-green leaves
• ‘Redbor’ — deep purple color.

Ornamental cabbages and kales do not tolerate summer heat, so in USDA zone 8a, purchase transplants in the fall at your local garden center. Until cool weather arrives, plants won’t have much color; leaf colors will intensify as the temperatures start to get cold. White, pink, or red pigments will begin to develop when temperatures dip below 50°F. Once acclimated in a site, ornamental cabbages and kale can survive temperatures as low as 5°F, so plants may last into spring.

These plants grow approximately 12-in. wide and 15-in. tall. Purchase plants appropriately sized for the location because plants will generally not get much bigger after they are planted in the garden, particularly if the roots are pot-bound.

When temperatures start cooling down, plant ornamental cabbage and kale in a sunny spot in moderately moist, rich soil. Prepare soil by incorporating 3 to 4 inches of organic matter and 2 pounds of a slow-release, 12-6-6 fertilizer per 100 square feet of bed space. Space them according to label recom-mendations – normally 12- to 18-in. apart. Bury stems so that the lowest leaves of the plants are flush with the soil sur-face. After planting, keep the plants well-watered. Add a good layer of mulch after planting to help stabilize soil temperatures and conserve moisture.

Form Jim Robbins CC BY-NC-ND 4.0

Position plants to best expose their colorful centers. Use them in mass plantings, in mixed or single container plantings, and as edgings. They look beautiful in the front of a border when combined with perennials that are at their peak in the fall, such as little bluestem grass (Schizacrium scoparium); tall, dark-leaved sedums (Sedum spp.); or asters (Aster spp.). For an easy and attractive container planting, place an ornamental cabbage or kale in the center of a container and surround it with pan-sies. Or try them with other plants that can tolerate light frosts (e.g., Swiss chard, snapdragons, petunias, or chrysanthemums).

Cabbage worms, cabbage loopers, flea beetles, slugs, aphids, and caterpillars are insects that may affect the plants’ health. However, because ornamental cabbage and kale are typically grown late in the growing season, they usually have fewer problems with these pests than if they were grown earlier in the year.

Resources

• NC Extension Gardener Plant Toolbox:
  • Brassica oleracea: Ornamental Cabbage and Kale Group
• Wisconsin Extension: Ornamental Cabbage and Kale
• Georgia Extension: Brassicas taking center stage with kale, mustards and collards

By Kathryn Copley, Extension Master Gardener SM Volunteer, Brunswick County, NC. For more information on gardening in Brunswick County, please call the Brunswick County Cooperative Extension Office 910-253-2610