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What Is Tree Basil?

Basil is a base flavor for many ethnic cuisines. It has a varying anise to citrus flavor, and there are many varieties and sizes available with different growth habits. Tree basil is also called African basil or more properly Ocimum gratissimum. Tree basil grows as a shrub and can grow from 3 to nearly 10 feet tall. It is an herbaceous perennial plant that is used as a medicinal, tea and flavoring.


Ocimum gratissimum is a woody stemmed plant. It has a sweet, spicy clove fragrance and slightly hairy soft leaves. The leaves are lime-green. The plant's extreme growth height is the reason for the name tree basil, but it is not precisely a tree. Stems become woody as the plant matures, which often happens to herbs. Tree basil is frost tender and is suited for tropical to semitropical climates as a perennial. In other areas it is grown as an annual.


Tree basil is primarily grown in southeast Asia and also in parts of Africa. It grows along coastal scrub up into lower mountainous terrain. It is a part of the African savannah but in home cultivation is often used as a hedge. Tree basil is a full sun plant which requires temperatures above 50 degrees F to thrive, but its best growth is achieved at temperatures closer to 75 or 80 degrees. Tree basil is found growing wild and is popular in cultivation.


Tree basil is used most often in teas, but its white flowers may also be added to salads. The tea is said to have numerous herbal medicine properties derived from the essential oils. The oil is imported as a substitute for clove oil or thyme oil. The oil is also used as an insect repellent in its native regions. The leaves have ceremonial purposes in India and Indonesia. It is not widely cultivated or used in the United States except as a curiosity.

How to Grow

Tree basil can be propagated through seed or stem cuttings. Cuttings root readily with a little rooting hormone and a soil-less peat and sand mixture. Seeds should be sown indoors four to eight weeks before the date of the last frost. When seedlings bear two sets of true leaves, harden them off and plant them in a sunny, well-drained garden bed or container. Tree basil needs regular watering, but allow the pot or site to dry out between irrigation and then water deeply.

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