Ocimum americanum, hoary basil, is a small, grey-hairy wild basil of roadsides and wasteland in India and Africa, with a lemony or camphor-like scent. Despite its name it is native to Africa and Asia. Its seeds swell into gel in water like sabja, and in Tamil Nadu it is sometimes called nai thulasi, “dog tulsi”.
- Botanical name
- Ocimum americanum L.
- Family
- Lamiaceae
- Tamil
- Nai thulasi
- Hindi
- Kali tulsi
- Parts used
- Leaf
- Habit
- Hoary basil; Tamil thulasi is a shop word
- Last updated
- 2026-10-30
How to recognise Hoary basil
It is an upright, bushy annual, usually knee-high, with small, oval, slightly toothed leaves covered in fine grey hairs.
Small white or pale lilac flowers grow in whorls along slender spikes, and the calyx is densely hairy and greyish. The old name canum means “hoary”.
Crushed leaves smell lemony to camphor-like, depending on the strain.
Holy basil, Ocimum tenuiflorum, has purplish or green leaves with a clove scent. Sweet basil, Ocimum basilicum, has larger, smoother leaves.
Traditional use of Hoary basil
Kitchen
Leaves flavour some African and Asian dishes, and the seeds are soaked into drinks like sabja.
African and Asian food practice
Village use
Bunches are hung or burned in homes to keep mosquitoes and other insects away.
Indian village practice
Modern notes on Hoary basil
The essential oil varies widely between strains, with citral, camphor or methyl cinnamate dominating. Studies show some strains repel insects.
Lemon basil, Ocimum × africanum, is a hybrid of this species and sweet basil.
Hoary basil safety
Use the leaves as a culinary herb. Concentrated essential oils can irritate skin and should not be swallowed.
Ecology and sourcing
It is native to tropical Africa and the Indian subcontinent and grows on roadsides, field edges and wasteland.
It flowers through much of the year, attracting bees.
It self-seeds readily.
It is often the basil seen growing wild along village lanes and temple paths in the south.
Related plants
Also in Lamiaceae
Questions about Hoary basil
Is Hoary basil tulsi?
No. Holy basil, tulsi, is Ocimum tenuiflorum.
What older names does Ocimum americanum go by?
Ocimum canum.
Are the seeds of Hoary basil used like sabja?
Yes, they swell into gel in water.
Is Hoary basil the same as lemon basil?
No. Lemon basil is a hybrid of this species and sweet basil.
Sources
- Ocimum americanum L. — Plants of the World Online, Kew (search) (accessed 2026)
- Wikidata item Q3240154 (Ocimum americanum)
Educational page about a plant. It is not medical advice, not a diagnosis, and not an offer to sell. Traditional use is historical. If you need care, ask a licensed clinician. Questions: hello@meevamed.com.