An erect annual shrub grown for its fleshy red calyces, which surround the seed pod after flowering.
Roselle (Hibiscus sabdariffa, family Malvaceae) is an upright, usually branched plant, annual or living several years, up to 4.5 metres tall, whose stems often become woody at the base. It is an important multi-purpose plant giving food, medicine and other products. It has been grown as a food crop for around 6,000 years, probably originating in tropical central or western Africa, and it is still widely cultivated in the tropics and subtropics for food and fibre. It is also grown as an ornamental for its decorative red stalks, and the plant, especially its calyces, is traded internationally. The database notes that the seed oil might contain toxic substances.
It is best suited to humid lowland tropics up to about 600 metres, with 1,500 to 2,000 mm of rain a year, well distributed, though it tolerates much less or much more. It takes a warmer, more humid climate than its relative kenaf (Hibiscus cannabinus) but is more easily damaged by frost and fog. It needs full sun, does not tolerate shade and must be kept weeded; it does best on a friable sandy loam with humus but adapts to many soils, and its deep roots let it withstand some drought. It is sensitive to day length and flowers only when days are short, about 11 hours. Harvesting can begin three to five months after sowing. Seed germinates fairly quickly without treatment, faster if soaked or nicked, and cuttings of half-ripe wood root readily.
Source: Useful Tropical Plants database (Fern, K.).
Calyx infusions (a sour "tea") are used traditionally for high blood pressure, fever, and as a diuretic; studied for effects on blood pressure and cholesterol.
Fresh or dried calyces are brewed into a tart red drink (zobo/bissap) and used in jams; young leaves are cooked as a sour vegetable.
Grown as an annual crop from seed; widely cultivated across Nigeria and West Africa for its calyces and leaves.