Ornamental cabbage (Brassica oleracea) is a popular choice for gardeners seeking vibrant color when most other plants fade. This plant is cultivated for its striking, decorative foliage, which comes in shades of white, pink, purple, and red. Its appeal lies in its cold-hardiness, allowing it to provide late-season visual interest throughout the fall and winter months. Although it is the same species as edible cabbage, this ornamental variety has been selectively bred for its dramatic appearance.
Lifespan in the Landscape
Ornamental cabbage is technically a biennial plant, meaning it completes its life cycle over two years, but it is typically grown as a cool-season annual. The plant’s decorative display begins in the fall and often lasts well into the winter season. Cooler temperatures trigger the development and intensification of the vibrant colors in the central rosette of leaves.
The end of the ornamental display is primarily determined by the weather and the plant’s natural life cycle. The foliage will remain attractive until consistent, warmer spring temperatures arrive, usually when the average temperature rises above 60°F. At this point, the plant will begin to “bolt,” sending up a tall, unattractive flower stalk as it prepares to set seed. While the plant can tolerate light frosts, sustained severe freezes can cause significant damage or death, abruptly ending the display. In regions with mild winters, it can continue to provide color for several months, sometimes lasting until the following spring.
Extending Outdoor Display
Maximizing the duration of ornamental cabbage in the garden requires providing optimal growing conditions. The plants perform best when situated in a location that receives full sun, though they can tolerate partial shade, particularly in warmer climates. Well-draining, organically rich soil is necessary, as soggy conditions can lead to root rot and premature decline.
Consistency in watering is important; the soil should be kept moderately moist, but never waterlogged. Over-fertilization should be avoided after planting, as excess nitrogen can lead to rapid, leggy growth and duller leaf colors, counteracting the plant’s ornamental appeal. These plants are susceptible to common brassica pests, such as cabbage worms and aphids, which should be monitored and controlled to prevent foliage damage that shortens the display.
Winter care focuses on insulating the plant’s root system and maintaining stable soil temperature. Applying a thick layer of organic mulch, such as straw or shredded bark, around the base helps prevent the freeze-thaw cycles that can heave the plant out of the soil. This process, known as frost heaving, damages the roots and exposes the crown to drying winds. Proper mulching ensures the plant remains firmly anchored and protected, allowing it to withstand colder temperatures and reach its maximum natural lifespan.
Longevity as a Cut Specimen
Ornamental cabbage is a popular feature in indoor arrangements, valued for its rosette shape and long vase life. When harvested for use as a cut specimen, the stem should be severed with a sharp knife or shears, making a clean, angled cut. This angled cut increases the surface area for water absorption, which is particularly important for the plant’s thick, fibrous stem.
The cut specimen typically maintains its appearance for 10 days to two weeks, often outlasting many traditional cut flowers. To condition the stem, all foliage that would sit below the water line must be removed to prevent decay and bacterial growth in the vase water. The use of a floral preservative containing a biocide is highly recommended, as it helps keep the water clean and combats the slight, natural “cabbage smell” that can develop.
The arrangement should be placed in a cool location, away from direct sunlight, heat sources, and ripening fruit, which emits ethylene gas that accelerates plant aging. Changing the water and recutting a small portion of the stem every few days further helps maximize the longevity of the decorative display indoors. Keeping the water consistently fresh is the most effective step to ensure the specimen reaches its full two-week potential.