Cymbopogon nardus aka Giant Turpentine Grass

Cymbopogon nardus is a scented grass in the Poaceae family. It is a perennial, so it lives for many years. Its common names include citronella grass and Ceylon citronella. Kew gives its native range as South Sudan to southern Africa, and Indo-China. It grows in tropical regions that have a dry season. In Uganda, it grows on hills in grassland and open woodland. It is not native to Britain or Ireland.

This evergreen grass grows in clumps from a thick rootstock. Useful Tropical Plants gives a height of about 6.6 feet [2 metres]. Its fuller account gives an upper height of 8.2 feet [2.5 metres]. The plant's scent makes it useful as an oil crop. Growers raise it in tropical areas, such as Sri Lanka. There, it copes with poor soils and drought. These traits help sustain its use there.

Grow it in full sun, in soil that holds moisture. It prefers acid soil with a pH of 4.5 to 6. It can cope with a wider pH range, from 4 to 8. It grows best at daytime temperatures of 20–30°C. The source gives a range of 16–36°C that it can withstand. This does not show how well it copes with frost. It prefers 1,300–2,000 millimetres of rain each year. It can withstand a much wider range of rainfall. It copes with drought, but dry soil does not suit it best.

Grow plants from seed, or split clumps that have taken hold. Sow seed on the surface, or add a thin cover. Move young plants into their own pots at three or four leaves. Weeds can crowd plants grown from seed sown straight in the ground. Split clumps each year to help stop crowding and poor growth. Shoots split from the clump may fail to take root. The first leaf harvest for oil can start after about 240 days. Later harvests can follow every 90–120 days.

The leaves add flavour to soups and curries. They also make a scented tea. The white inner stem adds flavour too. Industry uses the essential oil in foods, soaps, perfumes and polishes. It also uses the oil in insecticides, which kill insects. Steam distillation draws oil from the whole plant. In traditional medicine, people steep leaves for digestive spasms and colds. These uses do not prove that it has health benefits. Useful Tropical Plants lists no known hazards. This does not prove that every preparation is safe.