Ocimum gratissimum: complete guide

Overview

Ocimum gratissimum, commonly known as African basil or tree basil, is a herbaceous to shrubby plant from the Lamiaceae family. This tropical to subtropical species originates from Africa, India, and other warm regions worldwide. It is renowned for its highly aromatic leaves with a strong, unique fragrance resembling cloves with citrus overtones. In tropical regions it grows as a perennial shrub; in temperate climates as an annual plant.

Appearance and Bloom

African basil grows as an upright, compact shrub reaching 60-100 cm tall. The leaves are small, dark green, lance-shaped with robust texture and highly aromatic. They contain a strong essential oil. The flowers are small, white to light purple, grouped in long spikes, appearing from summer to fall. The entire plant is strongly fragrant, especially when leaves are touched.

Ideal Location

Ocimum gratissimum thrives best in full sun with 6-8 hours direct sunlight daily. The plant is thermophilic and grows best in warm to hot climates. In temperate climates it can grow in containers and move indoors during frost periods. Provide shelter from strong winds.

Soil

This plant grows best in well-draining, moist but not waterlogged soil. A pH range of 6.5 to 7 is ideal. Add organic matter at planting time. The plant doesn't require special feeding but will thrive with regular balanced fertilizer applications. Avoid heavy, waterlogged soils.

Watering

Water regularly during the growing season, especially in hot periods. Soil should remain consistently moist but not waterlogged. Allow soil to dry between waterings. In extreme heat daily watering may be needed. Reduce watering in winter or when growth slows.

Pruning

Pruning helps maintain a compact, full form. Regularly pinch off growing tips to encourage branching. This also makes the plant more productive for leaf production. Remove flowers if you're only interested in leaf production. In tropical climates pruning can occur year-round; in temperate climates especially in summer.

Maintenance Calendar

Spring: Start from seedlings or purchase young plants; plant after last frost. Summer: Water regularly, prune weekly for productive growth. Fall: Harvest leaves for drying or storage; reduce watering. Winter: In cold climates move indoors or treat as annual.

Winter Hardiness

Ocimum gratissimum is not cold-hardy and tolerates no frost. In zones colder than 10 it must be grown as an annual or moved indoors in containers during winter. The plant can overwinter in mild climates and will regrow in the next season.

Companion Plants

African basil combines well with other aromatic herbs such as rosemary, lavender, and oregano in an herb garden. The fine white flowers harmonize with purple and blue flowers. Plant it near seating areas to enjoy the fragrance.

Conclusion

Ocimum gratissimum is a fascinating addition to herb gardens, especially in warm climates. Its strong fragrance, attractive form, and potential uses make it a valuable plant for culinary and medicinal purposes, as well as an ornamental addition.

Available at: Specialized herb nurseries and garden centers focusing on exotic and tropical plants.