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Cardinal Basil

Ocimum basilicum 'Cardinal'

A spectacular ornamental basil variety that produces vibrant red-purple flower spikes rising above green foliage, creating a stunning display that attracts pollinators while providing excellent basil flavor. This unique variety was bred specifically for its dramatic flowering display and long-lasting blooms, making it perfect for edible landscaping. The flowers are edible with intense basil flavor, while leaves maintain classic sweet basil taste.

Harvest

65-75d

Days to harvest

📅

Sun

Full sun

☀️

Zones

10–10

USDA hardiness

🗺️

Height

0-3 feet

📏

Planting Timeline

Zone:

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Start Indoors

Transplant

Harvest

Start Indoors

Transplant

Harvest

Showing dates for Cardinal Basil in USDA Zone 10

All Zone 10 herb →

Zone Map

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Cardinal Basil · Zones 10–10

What grows well in Zone 10? →

Growing Details

Difficulty

Easy

Spacing8-12 inches

SoilRich, well-draining soil with organic matter

pH6.0-7.0

Water1-1.5 inches per week, consistent moisture

SeasonWarm season annual

FlavorClassic sweet basil flavor in leaves, intense basil-clove flavor in flowers

ColorMedium green leaves with bright red-purple flower spikes

Size1-2 inch oval leaves, 4-6 inch flower spikes

Zone-by-Zone Planting Calendar

Zone	Indoor Start	Transplant	Direct Sow	Harvest
Zone 10	January – January	February – April	—	April – December

Complete Growing Guide

Drainage: Good Drainage, Moist. Height: 0 ft. 4 in. - 3 ft. 0 in.. Spread: 0 ft. 4 in. - 1 ft. 2 in.. Spacing: 12 inches-3 feet. Growth rate: Rapid. Maintenance: Low. Propagation: Seed, Stem Cutting. Regions: Coastal, Mountains, Piedmont.

Harvesting

Bloom time: Summer

Edibility: Leaves and flowers in tea, as flavoring

Storage & Preservation

Fresh Cardinal basil leaves stay crisp for 7-10 days when stored like cut flowers—trim stems and place in water, cover loosely with a plastic bag, and keep at room temperature. Never refrigerate fresh basil leaves as they'll turn black from cold damage.

The spectacular flower spikes maintain their color and flavor for 3-5 days in water at room temperature, making them excellent for fresh garnishes. For long-term storage, dry both leaves and flowers by hanging in bundles in a warm, dry, dark location for 2-3 weeks. Properly dried Cardinal basil retains good color and strong flavor for up to one year.

Freeze leaves in ice cube trays with olive oil for easy portioning in winter cooking. The colorful flowers make exceptional herbal vinegars—steep fresh flower spikes in white wine vinegar for 2-3 weeks for both beautiful color and intense basil flavor.

History & Origin

Origin: Tropical Africa and Asia

Advantages

+Edible: Leaves and flowers in tea, as flavoring
+Fast-growing
+Low maintenance

Companion Plants

Plant Together

Tomatoes

Basil repels tomato hornworms and aphids while potentially improving tomato flavor

Peppers

Basil deters aphids, spider mites, and thrips that commonly attack pepper plants

Oregano

Both herbs have similar growing requirements and oregano helps repel aphids and cucumber beetles

Marigolds

Repel nematodes and aphids while attracting beneficial insects that protect basil

Lettuce

Basil provides light shade for lettuce in hot weather and repels aphids that damage leafy greens

Chives

Repel aphids and may improve basil's essential oil production and overall flavor

Nasturtiums

Act as trap crops for aphids and cucumber beetles while attracting beneficial predatory insects

Parsley

Compatible growth habits and parsley attracts beneficial insects that help protect basil

Keep Apart

Rue

Allelopathic properties inhibit basil growth and can stunt development

Common Sage

Competes aggressively for nutrients and may inhibit basil growth through root competition

Fennel

Produces allelopathic compounds that inhibit growth of basil and most other garden plants

Nutrition Facts

Calories

23kcal(1%)

Protein

3.15g(6%)

Fiber

1.6g(6%)

Carbs

2.65g(1%)

Fat

0.64g(1%)

Vitamin C

18mg(20%)

Vitamin A

264mcg(29%)

Vitamin K

415mcg(346%)

Iron

3.17mg(18%)

Calcium

177mg(14%)

Potassium

295mg(6%)

Per 100g serving. % Daily Value based on 2,000 calorie diet. Source: USDA FoodData Central (FDC #172232)

Pests & Disease Resistance

Resistance

Good resistance to downy mildew, fusarium wilt susceptible

Common Pests

Aphids, spider mites, Japanese beetles, slugs

Diseases

Fusarium wilt, bacterial leaf spot, downy mildew in humid conditions

Frequently Asked Questions

How long does Cardinal basil take to flower?▼

Cardinal basil typically begins producing its signature red-purple flower spikes 8-10 weeks after transplanting, or about 65-75 days from seed. The first spikes usually appear in mid to late summer and continue flowering until frost. For best flower production, ensure plants receive full sun and consistent moisture.

Can you grow Cardinal basil in containers?▼

Yes, Cardinal basil grows excellently in containers. Use pots at least 12 inches wide and deep with drainage holes. The dramatic flower spikes make stunning container displays on patios or decks. Container plants may need daily watering in hot weather and benefit from afternoon shade in zones 8-10.

Are Cardinal basil flowers edible?▼

Cardinal basil flowers are completely edible and offer intense basil-clove flavor that's more concentrated than the leaves. The vibrant red-purple spikes make beautiful garnishes for salads, cocktails, and desserts. Harvest flower spikes when fully colored but before individual flowers begin to fade for best flavor and appearance.

What does Cardinal basil taste like?▼

Cardinal basil leaves have classic sweet basil flavor similar to Genovese varieties, making them excellent for pesto and Italian dishes. The flowers provide much more intense flavor with pronounced clove notes. This variety maintains good leaf flavor even during heavy flowering, unlike many basil varieties that become bitter when blooming.

Is Cardinal basil good for beginners?▼

Cardinal basil is relatively beginner-friendly with standard basil care requirements. However, its susceptibility to fusarium wilt and need for consistent watering make it slightly more challenging than regular sweet basil. New gardeners should focus on good drainage and avoiding overhead watering to prevent disease issues.

When should I plant Cardinal basil seeds?▼

Start Cardinal basil seeds indoors 4-6 weeks before your last expected frost date, or direct sow outdoors once soil temperature reaches 65°F consistently. In most areas, this means starting seeds indoors in March-April for transplanting in May-June. Cold soil will stunt growth permanently, so patience with timing is crucial.