Tagetes patula hybrids, Photo: Michael Lahanas
The French marigold (Tagetes patula) is a species in the daisy family (Asteraceae).
The flower is an annual, growing to 0.5 m by 0.3 m. It is in flower from July to October, and the seeds ripen in September. The flowers are hermaphrodite (having both male and female organs) and are pollinated by insects. They are noted for attracting wildlife. The leaves of the marigold are coated with oily glands that produce a pungent scent.
Used mainly as an edging plant on herbaceous borders, it is a low growing plant with flowers of blended red and yellow in most varieties. Liquid concentrate from the flower and leaves is said to be used medicinally in eastern culture to stop nasal bleeding.
In addition to colouring foods, yellow dye from the flowers is also used to colour textiles.
The whole plant is harvested when in flower and distilled for its essential oil. The oil is used in perfumery; it is blended with sandalwood oil to produce 'attar genda' perfume. About 35 kilograms of oil can be extracted from 1 hectare of the plant (yielding 2,500 kg of flowers and 25,000 kg of herbage). The oil is also being investigated for antifungal activity, including treatment of candidiasis and treating fungal infections in plants.
The plant is used in companion planting for many vegetable crops. Its root secretions kill nematodes in the soil and it is said to repel harmful insects, such as white fly amongst tomatoes.
Source: Wikispecies, Wikipedia: All text is available under the terms of the GNU Free Documentation License