Botanical Name : Hibiscus sabdariffa
Common Names: Roselle
Habitat:Roselle is native from India to Malaysia, where it is commonly cultivated, and must have been carried at an early date to Africa. It has been widely distributed in the Tropics and Subtropics of both hemispheres, and in many areas of the West Indies and Central America has become naturalized.
Hibiscus sabdariffa is an annual/perennial, erect, bushy, herbaceous subshrub to 8 ft (2.4 m) tall, with smooth or nearly smooth, cylindrical, typically red stems. The leaves are alternate, 3 to 5 in (7.5-12.5 cm) long, green with reddish veins and long or short petioles. Leaves of young seedlings and upper leaves of older plants are simple; lower leaves are deeply 3- to 5- or even 7-lobed; the margins are toothed. Flowers, borne singly in the leaf axils, are up to 5 in (12.5 cm) wide, yellow or buff with a rose or maroon eye, and turn pink as they wither at the end of the day. At this time, the typically red calyx, consisting of 5 large sepals with a collar (epicalyx) of 8 to 12 slim, pointed bracts (or bracteoles) around the base, begins to enlarge, becomes fleshy, crisp but juicy, 1 1/4 to 2 1/4 in (3.2-5.7 cm) long and fully encloses the velvety capsule, 1/2 to 3/4 in (1.25-2 cm) long, which is green when immature, 5-valved, with each valve containing 3 to 4 kidney-shaped, light-brown seeds, 1/8 to 3/16 in (3-5 mm) long and minutely downy. The capsule turns brown and splits open when mature and dry. The calyx, stems and leaves are acid and closely resemble the cranberry (Vaccinium spp.) in flavor.
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A minor ornamental in Florida and elsewhere is the red-leaf hibiscus, H. acetosella Welw. (syn. H. eetveldeanus Wildem. & Th.) of tropical Africa, which has red stems to 8 ft (2.4 m) high, 5-lobed, red or bronze leaves, and mauve, or red-striped yellow, flowers with a dark-red eye, succeeded by a hairy seed pod enclosed in a red, ribbed calyx bearing a basal fringe of slender, forked bracts. This plant has been often confused with roselle, though its calyx is not fleshy and only the young leaves are used for culinary purposes–usually cooked with rice or vegetables because of their acid flavor.
Prefers a well-drained humus rich fertile soil in full sun. Roselle requires a permeable soil, a friable sandy loam with humus being preferable; however, it will adapt to a variety of soils. It is not shade tolerant and must be kept weed-free. It will tolerate floods, heavy winds or stagnant water. Roselle is reported to tolerate an annual precipitation of 64 to 429cm, an annual temperature in the range of 12.5 to 27.5°C and a pH of 4.5 to 8.0. This species is not hardy in Britain, but it can be grown as a half-hardy annual, flowering in its first year from seed. Plants are sensitive to the length of daylight and do not flower if there are more than 13 hours of light in the day. Roselle is widely cultivated in the Tropical and Sub-tropical zones for its fibre and edible calyx, there are some named varieties. Roselle is best suited to tropical climates with a well-distributed rainfall of 1500 – 2000 mm yearly, from sea-level to about 600 m altitude. It tolerates a warmer and more humid climate than kenaf (Hibiscus cannabinus), but is more susceptible to damage from frost and fog. Plants exhibit marked photoperiodism, not flowering at shortening days of 13.5 hours, but flowering at 11 hours. In the United States plants do not flower until short days of late fall or early winter. Since flowering is not necessary for fibre production, long light days for 3 – 4 months is the critical factor. There are two main forms of the plant:- var. sabdariffa has red or pale yellow inflated edible calyces but a poor quality fibre; var. altissima is grown for its fibre but has inedible calyces. Plants have a deep penetrating taproot.
Seed – sow early spring in a warm greenhouse. Germination is usually fairly rapid. Prick out the seedlings into individual pots when they are large enough to handle. If growing them as annuals, plant them out into their permanent positions in early summer and protect them with a frame or cloche until they are growing away well. If hoping to grow them as perennials, then it is better to grow them on in the greenhouse for their first year and to plant them out in early summer of the following year. Cuttings of half-ripe wood, July/August in a frame. Overwinter them in a warm greenhouse and plant out after the last expected frosts.
The fresh calyx (the outer whorl of the flower) is eaten raw in salads, is cooked and used as a flavouring in cakes etc and is also used in making jellies, soups, sauces, pickles, puddings etc. The calyx is rich in citric acid and pectin and so is useful for making jams, jellies etc. It is also used to add a red colour and to flavour to herb teas, and can be roasted and used as a coffee substitute. A refreshing and very popular beverage can be made by boiling the calyx, sweetening it with sugar and adding ginger. Tender young leaves and stems – raw or cooked. Used in salads, as a potherb and as a seasoning in curries, they have an acid, rhubarb-like flavour. Seed – roasted and ground into a powder then used in oily soups and sauces. The roasted seeds have been used as a coffee substitute that is said to have aphrodisiac properties. Root – it is edible but very fibrousy. Mucilaginous, without very much flavour. The seed yields 20% oil. (This is probably edible).
Roselle is an aromatic, astringent, cooling herb that is much used in the Tropics. It is said to have diuretic effects, to help lower fevers and is antiscorbutic. The leaves are antiscorbutic, emollient, diuretic, refrigerant, and sedative. The leaves are very mucilaginous and are used as an emollient and as a soothing cough remedy. They are used externally as a poultice on abscesses. The fruits are antiscorbutic. The flowers contain gossypetin, anthocyanin, and the glycoside hibiscin. These may have diuretic and choleretic effects, decreasing the viscosity of the blood, reducing blood pressure and stimulating intestinal peristalsis. The leaves and flowers are used internally as a tonic tea for digestive and kidney functions. Experimentally, an infusion decreases the viscosity of the blood, reduces blood pressure and stimulates intestinal peristalsis. The ripe calyces are diuretic and antiscorbutic. The succulent calyx, boiled in water, is used as a drink in the treatment of bilious attacks. The seeds are diuretic, laxative and tonic. They are used in the treatment of debility. The bitter root is aperitif and tonic. The plant is also reported to be antiseptic, aphrodisiac, astringent, cholagogue, demulcent, digestive, purgative and resolvent. It is used as a folk remedy in the treatment of abscesses, bilious conditions, cancer, cough, debility, dyspepsia, dysuria, fever, hangover, heart ailments, hypertension, neurosis, scurvy, and strangury. One report says that the plant has been shown to be of value in the treatment of arteriosclerosis and as an intestinal antiseptic, though it does not say which part of the plant is used. Simulated ingestion of the plant extract decreased the rate of absorption of alcohol, lessening the intensity of alcohol effects in chickens.
In India, Africa and Mexico, all above-ground parts of the roselle plant are valued in native medicine. Infusions of the leaves or calyces are regarded as diuretic, cholerectic, febrifugal and hypotensive, decreasing the viscosity of the blood and stimulating intestinal peristalsis. Pharmacognosists in Senegal recommend roselle extract for lowering blood pressure. In 1962, Sharaf confirmed the hypotensive activity of the calyces and found them antispasmodic, anthelmintic and antibacterial as well. In 1964, the aqueous extract was found effective against Ascaris gallinarum in poultry. Three years later, Sharaf and co-workers showed that both the aqueous extract and the coloring matter of the calyces are lethal to Mycobacterium tuberculosis. In experiments with domestic fowl, roselle extract decreased the rate of absorption of alcohol and so lessened its effect on the system. In Guatemala, roselle “ade” is a favorite remedy for the aftereffects of drunkenness.
In East Africa, the calyx infusion, called “Sudan tea”, is taken to relieve coughs. Roselle juice, with salt, pepper, asafetida and molasses, is taken as a remedy for biliousness.
The heated leaves are applied to cracks in the feet and on boils and ulcers to speed maturation. A lotion made from leaves is used on sores and wounds. The seeds are said to be diuretic and tonic in action and the brownish-yellow seed oil is claimed to heal sores on camels. In India, a decoction of the seeds is given to relieve dysuria, strangury and mild cases of dyspepsia and debility. Brazilians attribute stomachic, emollient and resolutive properties to the bitter roots.
A strong fibre obtained from the stem (called rosella hemp) is used for various household purposes including making sackcloth, twine and cord. A yellow dye is obtained from the petals. It is used in medicines etc. The seed yields 20% oil.
The seeds are considered excellent feed for chickens. The residue after oil extraction is valued as cattle feed when available in quantity.
Disclaimer : The information presented herein is intended for educational purposes only. Individual results may vary, and before using any supplement, it is always advisable to consult with your own health care provider.