Flowering kale and cabbage (Brassica oleracea var. acephala) are used to dress up the cool-season garden with colorful foliage. Both flowering kale and flowering cabbage are similar plants that belong to the same species. The difference lies in the leaf shape. Flowering kale tends to have crinkled or frilly leaves, while flowering cabbage tends to have smooth leaves. Flowering kale and cabbage grow as a biennial in U.S. Department of Agriculture plant hardiness zones 3 through 9. This ornamental is most commonly grown as an annual.
Flowering kale and cabbage have an open leaf formation and are more closely related to wild kale varieties than the domestic culinary kale. As the foliage develops in a rosette pattern, the outer green leaves remain green while the inner leaves develop in a contrasting color. The open growth habit makes the inner leaves strikingly visible. These inner colorful leaves are often called a flower because of their ornamental value, but the inner leaves are not true flowers and will not produce seeds.
Though flowering kale and cabbage are biennial plants, this kind of cabbage is most commonly grown as an annual for its ornamental value. Biennials take two years to complete the growth cycle and commonly only flower towards the end of the second growing season. If you grow flowering kale and cabbage as annual plants, you will likely never see a true flower. If you leave flowering kale and cabbage in the ground until the second growing season, the plants will produce a true flower followed by seeds.
Climate and Growing Conditions
Cool weather produces the best colors in flowering kale and cabbage . When temperatures drop below 60 degrees Fahrenheit, ideally between 45 and 55 F, the color in the center intensifies. In Mediterranean climates, where winters are cool and damp and summers get hot, grow flowering kale and cabbage as a cool season annual. Plant new plants or starts in late summer and fall and replace the plants with heat-loving annuals the following spring when the weather heats up.
Warm weather can stimulate flower production at the end of the first growing season, which is why this biennial is commonly grown as an annual. Once flowering kale produces a true flower, its ornamental value is diminished. The long flower stalk emerges from the center of the leaves and is topped by a yellow flower. Warm weather will also cause the colorful leaves to fade. At this point, unless you want to collect the seeds, its best to remove the plants and replace them with other heat-tolerant annuals.
Edible and Ornamental
Flowering kale and cabbage, also commonly called ornamental kale or cabbage, are both showy and edible. The leaves are tougher than culinary kale, and the flavor less enticing, but the colorful leaves add a dressy element when used as a garnish or added to winter salads. The color and leaf shape varies by cultivar and includes varieties with deep purple to red centers, pink, white and cream colors.
- University of California Center for Landscape and Urban Horticulture: Ornamental Kale
- Washington State University Plant of the Month: Kale
- University of Florida IFAS Extension: Brassica Oleracea Flowering Kale, Ornamental Cabbage
- UCC Biology Department: Flowering Cabbage and Kale
- UMass Amherst: Flowering Cabbage and Kale
- Floridata: Brassica Oleracea var. Capitata
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