Annuals

Ocimum basilicum 'African Blue'

African Blue Basil

LamiaceaeAfrica

At a Glance

Typeannual herb
Habitupright
Foliagedeciduous
Height3-4 feet
Width18-24 inches
Maturity0.25 years

Growing Zones

USDA Hardiness Zones

9a - 11b
Zone 9a
Zone 9b
Zone 10a
Zone 10b
Zone 11a
Zone 11b
These zones indicate the coldest temperatures this plant can typically survive.
Frost Tolerancetender

Key Features

Attracts Pollinators
Attracts Butterflies
Fragrant (strong)
Container Friendly
Maintenancemoderate

Overview

Ocimum basilicum 'African Blue' is a distinctive hybrid basil cultivar that combines the aromatic qualities of sweet basil with the ornamental appeal of purple flowering basil. This vigorous annual herb produces sturdy, upright stems clothed in attractive oval to lance-shaped leaves that display a rich green color with purple-tinged veins and undersides. The foliage exhibits the characteristic basil fragrance with complex aromatic notes that blend sweet, spicy, and slightly camphor-like scents. The plant's most striking feature is its abundant production of dense, cylindrical flower spikes that emerge in late summer. These impressive purple-blue inflorescences can reach 6-8 inches in length and are densely packed with small tubular flowers that attract bees, butterflies, and other pollinators. Unlike many basil varieties that become bitter when allowed to flower, Ocimum basilicum 'African Blue' maintains its culinary value even during bloom, making it both a productive herb and an ornamental garden specimen.

Native Range

Ocimum basilicum originated in tropical regions of Africa and Asia, particularly India and Southeast Asia. This specific cultivar 'African Blue' is a modern hybrid developed through selective breeding programs that combined sweet basil genetics with purple-flowered basil varieties.

Suggested Uses

Ocimum basilicum 'African Blue' works well in herb gardens, mixed borders, and container plantings where its ornamental purple flowers can be appreciated. Excellent for culinary use in Mediterranean and Asian cuisine, with leaves suitable for fresh use, drying, or oil infusion. The attractive flower spikes make excellent cut flowers for arrangements and are valuable for pollinator gardens. Ideal for edible landscaping where both beauty and function are desired.

How to Identify

Ocimum basilicum 'African Blue' can be identified by its distinctive combination of green leaves with purple-tinged veins and undersides, paired with prominent purple-blue flower spikes that appear in late summer. The plant has a robust, upright growth habit reaching 3-4 feet in height, with sturdy square stems characteristic of the mint family. The leaves are oval to lance-shaped, typically 2-3 inches long, and emit a complex basil fragrance when crushed. The dense, cylindrical flower spikes are particularly diagnostic, measuring 6-8 inches long and displaying rich purple-blue coloration that distinguishes it from other basil cultivars.

Appearance

Size & Dimensions

Height3' - 4'
Width/Spread1'6" - 2'

Reaches mature size in approximately 0.25 years

Colors

Flower Colors

purple
blue

Foliage Colors

green
purple

Bloom Information

Bloom Period

~16 weeks
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SummerFall
late summer through fall

Detailed Descriptions

Flower Description

purple-blue

Foliage Description

green with purple-tinged veins and undersides

Growing Conditions

Sun Requirements

Full Sun
Requires 6-8 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 7.5(Neutral)
357912
Soil Types
loam
Drainage
well drained

Water & Climate

Water Needs

moderate

Frost Tolerance

tender

Time to Maturity

80-90 days

Care & Maintenance

Care Guide

Ocimum basilicum 'African Blue' requires warm conditions and consistent moisture for optimal growth. Plant in well-draining soil enriched with compost, providing at least 6-8 hours of direct sunlight daily. Water regularly to maintain evenly moist soil, but avoid waterlogging which can lead to root rot. Feed with a balanced liquid fertilizer every 2-3 weeks during the growing season, or incorporate slow-release fertilizer into the soil at planting. Pinch growing tips regularly to encourage bushy growth and continuous leaf production, though this cultivar can be allowed to flower without significant loss of flavor quality.

Pruning

Prune Ocimum basilicum 'African Blue' by pinching or cutting stem tips regularly throughout the growing season to promote branching and prevent legginess. Remove flower spikes if maximum leaf production is desired, though this variety maintains good leaf quality even when flowering. Harvest leaves frequently by cutting stems just above a pair of leaves, which encourages new growth. In late fall before frost, harvest remaining foliage for preservation or allow the plant to complete its lifecycle naturally.

Pruning Schedule

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summerfall

Maintenance Level

moderate

Container Growing

✓ Suitable for container growing

Minimum container size: 5 gallons

⚠️ Toxicity Warning

Ocimum basilicum 'African Blue' is generally safe for humans when used in normal culinary quantities. The leaves and flowers are edible and commonly used in cooking. However, large quantities of any basil may cause digestive upset in sensitive individuals. Generally considered safe for pets in small amounts, though large quantities could potentially cause mild gastrointestinal irritation in cats and dogs.

Planting Guide

Planting Methods & Timing

Planting Method

transplant

Indoor Start

6 weeks before last frost

Direct Sow Timing

after last frost when soil temperature reaches 60°F

Days to Maturity

80–90 days

Plant Spacing

12 inches

Companion Planting

Good Companions

tomatoes
peppers
oregano
marigolds
nasturtiums

Avoid Planting With

fennel
rue
sage