Newsletter Articles
How to Grow Ornamental Cabbage and Kale
By Richard Flowers, ACCNP-Green Thumb Nursery-Ventura
Grow ornamental cabbage and kale as a cool-season display: set out transplants in fall, in full sun and rich, moist, well-drained soil, and enjoy the rosettes of white, pink, and purple color through winter. The two most important things to know are that the color is in the leaves, not the flowers (the name is a bit of a misnomer), and that it only develops once nights turn cold, below about 50 degrees F. These are cold-hardy plants but they are not heat-tolerant, so they bolt and fade as spring warms up. Plant them in fall, and expect the color to deepen a few weeks after the first cool nights.
Quick answer: Ornamental cabbage and kale are colorful forms of the same species as edible cabbage, grown for their foliage rather than for eating. Set out transplants in fall in full sun and moist, well-drained soil. The bright center color is in the leaves, not flowers, and it only develops once night temperatures drop below about 50 degrees F, usually deepening over 2 to 4 weeks. They are cold-hardy but not heat-tolerant, so they are a fall-to-winter plant that bolts and declines when spring warms. Watch for cabbage worms and aphids, and know that while they are technically edible, they are grown for looks, not flavor.
| Type | Look | Key care |
|---|---|---|
| Ornamental cabbage | Broad, smooth leaves forming a rounded head with a colored center | Full sun; plant in fall; color after nights below 50 degrees F |
| Ornamental kale (fringed) | Ruffled, frilly leaf edges in an open rosette | Full sun; cool-season only; bolts in spring |
| Ornamental kale (feather) | Deeply cut, feathery leaves | Full sun; moist, well-drained soil |
What Are Ornamental Cabbage and Kale
Ornamental, or flowering, cabbage and kale are the very same species as the cabbage and kale you eat, Brassica oleracea, simply bred in cultivars with vivid colored leaves and grown for looks rather than the dinner plate. They form a wide rosette of crinkled foliage in shades of white, rose, pink, and purple.[1] The quick way to tell the two apart: ornamental cabbage has broad, flat leaves and forms a loose head, while ornamental kale has deeply cut, curly or frilly leaves in a tight rosette and does not form a head.[2] Horticulturally, the smooth-margined types are grouped as flowering cabbage and the fringed or divided types as flowering kale, which is further split into finely ruffled and feather-leaved forms.[3]
One thing to clear up right away: the word flowering is a misnomer. The colorful display is not a bloom at all; it is the central leaves of the plant that color up. There is no showy flower involved.[3]
Why the Color Needs Cold
This is the single most important thing to understand before you plant: the bright center color only appears once it gets cold. The pink, white, and purple pigments begin to develop when temperatures dip below about 50 degrees F.[2] The deeper color, NC State notes, intensifies as temperatures fall further below that mark.[1] The process is not instant: the central leaves lose their green chlorophyll after several nights below 50 degrees F, and it takes roughly 2 to 4 weeks from the start of cool nights to develop full, intense coloration.[3] In practice, that means a plant set out while fall is still warm will simply stay green until the nights finally turn cold, so do not panic if your new plants are not colorful yet.
How to Plant and Grow Them
Ornamental cabbage and kale are biennials that we grow as cool-season annuals, set out in fall as the weather cools.[1] The easiest approach is to buy transplants from the garden center in fall rather than starting from seed, which gives you a full display much faster.[2] In Southern California, the cool-season window lines up well: the University of California puts the South Coast planting time for this kind of crop in roughly August through October, with cool-season plants happiest at average temperatures around 55 to 75 degrees F.[4]
Give them full sun for the best leaf color, and plant them in amended, moist, well-drained soil, leaving each rosette room to reach its full width.[1] They are genuinely cold-hardy once established, surviving temperatures as low as 5 degrees F, which is far colder than a Southern California winter will ever deliver.[2] The catch is the other end of the thermometer: they have low heat tolerance and bolt, stretching up into a flower stalk and losing their tidy form, as temperatures warm in spring. Treat them as a fall-to-winter display, not a permanent planting.[5]
Care, Pests, and Whether You Can Eat Them
Day to day, these are low-maintenance plants: keep the soil consistently moist and give them that full-sun spot, and they largely take care of themselves.[1] Because they are true brassicas, they get the same pests as edible cabbage and kale: cabbage worms, cabbage loopers, aphids, and the occasional slug or flea beetle.[2] Reach for cultural and mechanical controls first: check the undersides of leaves and the center of the plant for eggs and caterpillars and pick them off, conserve the natural enemies like parasitic wasps that keep them in check, and if worms get ahead of you, the selective biological product Bt is effective against cabbage worms and loopers while sparing those beneficial insects.[6]
And yes, you can technically eat them, since they are the same species as edible cabbage, but they are bred for looks rather than flavor and tend to be tougher and more bitter, so there are better brassicas to grow for the kitchen. Enjoy them as a colorful garnish if you like, but think of them as a decorative plant first.[1] For more cool-season color to pair them with, see our guide to fun fall plants, our tips for growing mums, and our picks for winter garden color.
Want help picking out ornamental cabbage and kale and the right companions for a fall and winter display? Stop by any Green Thumb Nursery and our team can set you up with transplants and the cool-season color to go with them.
Ornamental Cabbage and Kale FAQ
How do you grow ornamental cabbage and kale?
Set out transplants in fall in a full-sun spot with moist, well-drained soil, giving each plant room to spread. Keep the soil consistently moist, watch for cabbage worms and aphids, and wait for cold nights to bring out the color. They are easy and low-maintenance.[1]
When do you plant ornamental cabbage and kale?
Plant in fall as the weather cools. In Southern California the cool-season window runs roughly August through October, which sets the plants up to color once nights turn cold.[4]
Why is my ornamental cabbage still green?
It is not cold enough yet. The center color only develops once night temperatures drop below about 50 degrees F, and it takes roughly 2 to 4 weeks of cool nights to reach full intensity. A plant set out in warm fall weather will stay green until the chill arrives.[3]
Can you eat ornamental cabbage and kale?
Technically yes, because they are the same species as edible cabbage and kale, but they are bred for color rather than flavor and tend to be tough and bitter. They are fine as a garnish, but there are much better brassicas to grow for eating.[1]
Do ornamental cabbage and kale come back every year?
No. They are biennials grown as cool-season annuals: they look their best through fall and winter, then bolt and decline as spring warms, since they do not tolerate heat. Plan to replace them each season.[5]
Sources
- [1] NC State Extension Plants, Brassica oleracea (Ornamental Kale Group): plants.ces.ncsu.edu
- [2] NC State Extension, Brunswick County, Ornamental Cabbage and Kale: brunswick.ces.ncsu.edu
- [3] UMass Extension, Flowering Cabbage and Kale: umass.edu
- [4] UC Master Gardener Program, Time of Planting: ucanr.edu
- [5] Texas Tech University Plant Resources, Ornamental Cabbage and Kale: depts.ttu.edu
- [6] UC IPM, Imported Cabbageworm (Cole Crops): ipm.ucanr.edu
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