Curly Kale (Brassica oleracea var. sabellica)
Overview:
Curly kale is a cool-season biennial grown as an annual for its nutritious, frilly leaves. A member of the Brassicaceae (mustard) family, it’s one of the most recognizable and hardy leafy greens in the vegetable garden. Valued for its cold tolerance, rich nutrient profile, and striking appearance, curly kale is both an edible powerhouse and a beautiful addition to edible landscapes and ornamental beds.

• Botanical Name: Brassica oleracea var. sabellica

• Common Names: Curly kale, Scots kale

• Family: Brassicaceae (Mustard or Cabbage Family)

• Plant Type: Leafy biennial (commonly grown as an annual)

• Native Range: Eastern Mediterranean and Asia Minor

Identification Features:

• Leaves: Deep green to blue-green leaves with tightly ruffled or curled edges. Texture is crinkly and somewhat leathery. Leaves form in a rosette on a thick central stem and grow upward and outward. Baby leaves are more tender; mature leaves become tougher with age.

• Stems: Thick and fibrous, typically light green to purplish depending on the cultivar. Leaves are attached alternately along the central stalk.

• Growth Habit: Erect and open with leaves growing up a single central stalk. Mature plants reach 1–2 feet tall and can continue producing leaves from the center as older leaves are harvested from the bottom.

• Color: Leaf color varies from bright green to blue-green to purple-green, depending on variety and climate.

Bloom Time (if allowed to flower):
In its second year, curly kale will bolt and produce small yellow flowers typical of the mustard family. However, most gardeners harvest it before this stage.

Habitat and Growing Conditions:

• Sunlight: Full sun to partial shade. Grows best with at least 6 hours of sunlight daily.

• Soil: Prefers fertile, well-drained soil high in organic matter with a slightly acidic to neutral pH (6.0–7.0).

• Watering: Consistent moisture is important; do not allow the soil to dry out completely. Mulch helps retain moisture and suppress weeds.

• Hardiness: USDA Zones 2–10. Tolerates frost and often becomes sweeter after a light freeze.

Notable Varieties:

• ‘Dwarf Blue Curled’: Compact and cold-hardy with deep blue-green curled leaves.

• ‘Winterbor’: Very cold-tolerant with tightly curled, dark green leaves.

• ‘Redbor’: Ornamental purple-stemmed kale with highly ruffled leaves.

Ecological and Human Uses:

• Edible: Extremely nutrient-dense—rich in vitamins A, C, and K, as well as calcium, iron, and antioxidants. Used raw in salads, blended in smoothies, sautéed, or added to soups and stews.

• Ornamental: Attractive enough for edible landscaping; purple and blue cultivars add visual contrast to beds.

• Wildlife: Can attract aphids, cabbage moths, and other brassica-loving pests, so companion planting may be beneficial.

Common Look-Alikes:

• Ornamental Kale (Brassica oleracea var. acephala): Grown for appearance; often more colorful with tighter rosettes but less palatable.

• Collard Greens: Leaves are flatter, smoother, and broader with a waxy texture.

• Mustard Greens: Leaves are more sharply lobed and have a spicy, peppery taste.

Growing Tips:

• Harvest outer leaves regularly to encourage continued production.

• Provide row cover to protect from pests like cabbage worms and aphids.

• Cold improves flavor—consider overwintering in mild climates.

• Avoid planting near other brassicas to reduce soil-borne disease risk and pest buildup.

Curly kale is a champion in the cool-season garden, offering beauty, productivity, and nutrition. Whether planted in rows or mixed into edible landscapes, this versatile green deserves a spot in every garden.