In the beginning there was kale. This attractive edible originated in Asia Minor and the eastern Mediterranean region, where it’s been cultivated for over 4,000 years. From it arose the others – cabbage, broccoli, cauliflower, Brussels sprouts, mustard and collards.
Traditional purple leafed curly kale works well in a container, as well as in the border.
Photo Credit: Felder Rushing
Green-leafed forms are often grown in the vegetable garden, but they can also be used in flower beds.
Photo Credit: James H. Schutte
The smaller flowering kale is grown for its rosettes of showy foliage.
Photo Credit: Maureen Gilmer
While many Americans today are familiar with this cool-season vegetable, few actually eat it. It’s primarily used to adorn the self-service salad bars across the land, displacing other green decorations, thanks to the plant’s wilt resistance.
The veggie is actually near the top of the list in terms of nutritional value, containing heart-healthy antioxidants such as beta-carotene, large amounts of vitamins A, C and E, and heavy doses of calcium, potassium and iron. But you don’t have to munch on the plant to gain benefit from it: Purple leafed kales like ‘Redbor’ or ‘Red Russian’ have recently gained prominence in flower beds, where they’re used as a winter annual along with pansies and dianthus in USDA Hardiness Zone 7 and south. Flowering kale, a closely related plant, is smaller in stature, but forming tight rosettes on the ground rather than upright, leafy growth. It’s more often used as a bedding plant. Both types excellent selections for mixed container plantings as well.
Curly leafed kale (Brassica oleracea (Acephala Group)) is a biennial, meaning it has a lifespan of two years. It can grow 2-3 feet tall with thick, usually crinkled, broadly linear, 18-inch-long leaves borne up the stalk at a 45-degree angle. These leaves have a waxy coat and usually come in shades of gray-green or purple. (Collards, a closely related type and the greens of choice in the southern US, have green, more spatulate leaves with little or no crinkling.)
Curly leafed kale tolerates temperatures as low as 10-15 degrees F without injury. (It may survive even lower temperatures, but the foliage will be severely burned.) Transplants can also be planted in late winter four to six weeks before the last frost date and grown as an accent for spring bulbs. If the plant survives freezing temperatures in winter, it’ll flower in spring. The blooms, while not the reason to grow kale, are produced at the ends of the elongating stem as the plant bolts in midspring. Flowers range from light to dark yellow, are about the size of a dime and consist of four petals (typical for all members of the mustard family). Seed is produced in an elongated capsule, and as it matures, the plant dies
Kale’s sweetness is brought out after a series of frosts, which helps break the starches into sugars. The leaves take on a strong flavor if stored longer than two weeks in the refrigerator, so picking as needed ensures the best flavor. Strip the lower leaves from the base of the plant as needed, too – leaf removal encourages new growth and ensures a prolonged harvest. Kale’s ready for harvest two months after planting. Good gardeners produce about one pound of kale leaves per foot of row, so keep that in mind when deciding how much to plant this attractive – and nutritious – veggie.
The plant isn’t finicky about soil types, but like most garden vegetables, it grows best in sunny, well-drained, fertile soils. Spring plants can go out six weeks before the frost-free date. In the fall, transplants should be set out in late August. Kale can also be seeded directly into the garden; the fall crop should be planted in August, and the spring crop by late February.