Guizotia abyssinica aka Niger

Guizotia abyssinica is an annual in the daisy family, Asteraceae. Its names include niger seed, ramtil, and oil seed. It comes from northeast tropical Africa, including Ethiopia. Its native climate has wet and dry seasons. People grow it as an oil crop in Africa and India. Records of its cultivation reach back to about 3000 BC. Growers have also raised it in Germany. It is not native to Britain or Ireland.

This upright herb has a sturdy form. It reaches about 6 feet [1.8 metres] in the garden. Another source gives an upper height of 6.6 feet [2 metres]. A strong taproot anchors the plant. Many side roots grow close to the soil surface. PFAF records leaves from May to October. It gives August to September as the flowering season. Seeds ripen from September to October. Each flower has both male and female organs. Yet the plant cannot fertilise itself. Bees and other insects pollinate its flowers.

Niger seed grows in sun or light shade. It prefers moist soil and grows well in rich ground. It can also cope with poor, acid soils. Sandy, loamy, and clay soils can all support it. Growth suffers on very light sand or gravel. Reported soil pH ranges from 5.5 to 7.5. The plant tolerates drought, though seedlings need moisture to sprout. Sow seed in spring where the plants will grow. Cover it with only a thin layer of soil. In warm weather, seeds may sprout within three to four days.

People fry the seeds or use them to season food. They also grind dried seeds and mix them into cakes. The seeds contain about 30 percent edible oil. This oil can replace olive oil in food. Other uses include soap, paint, and fuel for lamps. Growers also dig the plants into soil as green manure. Traditional treatments use seed oil for rheumatism and burns. Seed paste has served as a poultice for scabies. These reports describe uses, not proof that treatments work.

The flowers provide food for bees in planted beds. Few serious pests or diseases affect this crop. Sources report no known hazards, but provide no detailed safety assessment. In Britain, stray plants occur on waste ground and near oil mills. Bird seed can also spread it beyond planted sites. Its drought tolerance raises concern about weeds in warmer regions. Its need for short days and cross-pollination may limit spread.