Contact: Diane Relf, Extension Specialist, Environmental Horticulture
Posted April 1997
Home gardeners who wish to have year-round color in their flower beds and borders are faced with a dilemma in attempting to locate appropriate plants for use in late autumn and winter. One group of plants that has been developed to fit in this time slot are the ornamental cabbages and kales. Both are classified as Brassica oleracea (the same as edible cabbages, broccoli, and cauliflower), but the ornamentals are better for coloring the garden than they are for eating. While these plants are listed as flowering cabbage and kale, they are grown for their colorful leaves, not for their flowers.
If you remember their classifications and that, like the other plants in the species, they prefer cool weather, a planting of ornamental cabbage or kale will be colorful and satisfying in the home landscape. The ornamental cabbages look much the same as an edible cabbage, while the kales tend to have a more unfolded and fancy or cut leaf.
There are two main planting times for ornamental cabbage and kale in the fall. The first is late August through September (about the same time as fall garden mums); the second is after garden mums have finished flowering or have been frosted out, usually mid- to late October. Plants may also be set out in the spring and allowed to grow in place for nearly a year.
Later plantings have several advantages compared to earlier plantings. The white, pink, or red pigmentations for which the plants are noted do not appear until after several frosts or prolonged cool weather. Planting too early -- that is, during the dog days of August and early September -- can result in a plant that stretches, becomes leggy, and is relatively colorless. Planting before frosts also means that you will have to contend with cabbage loopers, whereas after frosts, ornamental cabbages and kales are relatively pest-free.
When buying ornamental cabbages or kales, there are several sizes that determine plant quality and value. They may be sold in cell packs (bedding plant flats) or in pots from 4 inches up to the 10-inch size.
Just as with any other garden plant, the larger the pot the more you will pay for the product. However, this is one crop in which paying more for a larger plant will usually pay off. When an ornamental cabbage or kale becomes root-bound in the pot, it will not enlarge in size even after it is planted into the garden or a larger pot. Since the goal of planting ornamental cabbages and kales in the landscape is to have a solid mass or border of color, paying less for smaller plants usually requires planting more plants in a given area and, as a result, a greater total cost to fill the bed.
A high-quality plant will have a very short or rosette-type stem, leaves of even length, no apparent damage by cabbage loopers (holes or patches eaten out of leaves), and a large plant size. Ideally, the plants selected for late planting are nearly or fully colored. Remember that the plants will generally not increase noticeably in size after planting in the garden, particularly if the roots are pot bound.
Those wishing to grow their own ornamental cabbage and kale from seed should sow the seeds as early as late July or early August. They may be directly sown in the final pot (e.g., a 6- or 8-inch pot) or sown in a seed flat and later transplanted into the final pot. If using the transplanting method, transplanting should be done soon after the cotyledons are expanded so that root growth is not slowed and the plant will continue to enlarge. Leggy seedlings may be replanted up to the cotyledons to prevent the plant from toppling over. Seeds may also be sown directly in the garden.
An attractive feature of these plants is that they are suited for outdoor growing in all areas of Virginia. Because of the varied climates in Virginia, an exact timing schedule for sowing and planting in the garden will depend on your local conditions. However, sowing should take place about six to ten weeks before the anticipated first light frost.
(Originally published by Kevin L. Grueber, Department of Horticulture, Virginia Tech, in The Virginia Gardener Newsletter, Volume 7, Number 10.)
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