Hibiscus sabdariffa
| Hibiscus sabdariffa | |
| Light: |  |
| Moisture: |  |
| Hardiness: | 10 |
| Soil pH: | 5.6-8.4 |
| Height: | 10' |
| Width: | 7' |
| Blooms: | Late Summer-Mid Fall |
| Edible Rating: |  |
| Medicinal Rating: |  |
| Tea: | Yes |
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Hibiscus sabdariffa (common name: roselle)
Propagation: 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.
Cultivation: Prefers a well-drained humus rich fertile soil in full sun[1]. Roselle requires a permeable soil, a friable sandy loam with humus being preferable; however, it will adapt to a variety of soils[2]. It is not shade tolerant and must be kept weed-free[2]. It will tolerate floods, heavy winds or stagnant water[2]. 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[2].
This species is not hardy in Britain, but it can be grown as a half-hardy annual, flowering in its first year from seed[1]. Plants are sensitive to the length of daylight and do not flower if there are more than 13 hours of light in the day[3].
Roselle is widely cultivated in the Tropical and Sub-tropical zones for its fibre and edible calyx, there are some named varieties[4]. 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[2]. It tolerates a warmer and more humid climate than kenaf (Hibiscus cannabinus), but is more susceptible to damage from frost and fog[2]. 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[2].
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[2].
Plants have a deep penetrating taproot[2].
Range: Tropics.
Habitat: Disturbed ground[5].
Edibility: 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[6][7][4][2]. The calyx is rich in citric acid and pectin and so is useful for making jams, jellies etc[8][2]. It is also used to add a red colour and to flavour to herb teas[5][2], and can be roasted and used as a coffee substitute[4].
A refreshing and very popular beverage can be made by boiling the calyx, sweetening it with sugar and adding ginger[4].
Tender young leaves and stems - raw or cooked[9][2][10]. Used in salads, as a potherb and as a seasoning in curries, they have an acid, rhubarb-like flavour[4][5][2].
Seed - roasted and ground into a powder then used in oily soups and sauces[9][4].
The roasted seeds have been used as a coffee substitute that is said to have aphrodisiac properties[2].
Root - it is edible but very fibrousy[11]. Mucilaginous, without very much flavour[11].
The seed yields 20% oil[6]. (This is probably edible[K]).
Medicinal: 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[6][5].
The leaves are antiscorbutic, emollient, diuretic, refrigerant, and sedative[2]. 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[2].
The fruits are antiscorbutic[2].
The flowers contain gossypetin, anthocyanin, and the glycoside hibiscin[2]. These may have diuretic and choleretic effects, decreasing the viscosity of the blood, reducing blood pressure and stimulating intestinal peristalsis[2]. The leaves and flowers are used internally as a tonic tea for digestive and kidney functions[6][5]. Experimentally, an infusion decreases the viscosity of the blood, reduces blood pressure and stimulates intestinal peristalsis[8].
The ripe calyces are diuretic and antiscorbutic[2]. The succulent calyx, boiled in water, is used as a drink in the treatment of bilious attacks[2].
The seeds are diuretic, laxative and tonic[2]. They are used in the treatment of debility[2].
The bitter root is aperitif and tonic[2].
The plant is also reported to be antiseptic, aphrodisiac, astringent, cholagogue, demulcent, digestive, purgative and resolvent[2]. 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[2].
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[2].
Simulated ingestion of the plant extract decreased the rate of absorption of alcohol, lessening the intensity of alcohol effects in chickens[2].
Usage: A strong fibre obtained from the stem (called rosella hemp) is used for various household purposes including making sackcloth, twine and cord[6][7][5][10].
A yellow dye is obtained from the petals[8]. It is used in medicines etc[6].
The seed yields 20% oil[6].
Pollinators: Insects
Soil: Can grow in light, medium, and heavy soils.
Drainage: Prefers well drained soil.
Seed Ripens: Mid Fall-Late Fall
Flower Type: Hermaphrodite
Links
References
- ↑ 1.0 1.1 Huxley, Anthony. The New Royal Horticultural Society Dictionary of Gardening. MacMillan Press, 1992.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 2.14 2.15 2.16 2.17 2.18 2.19 2.20 2.21 2.22 2.23 2.24 2.25 2.26 2.27 2.28 Duke, James. Handbook of Energy Crops. 1983.
- ↑ Buchanan, Rita. A Weavers Garden.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Facciola, Stephen. Cornucopia - A Source Book of Edible Plants. Kampong Publications, 1990.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 Bown, Deni. Royal Horticultural Society Encyclopaedia of Herbs and Their Uses. Dorling Kindersley, 1995.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 Komarov, Vladimir. Flora of the USSR. Gantner Verlag, 1968.
- ↑ 7.0 7.1 Hill, Albert. Economic Botany. The Maple Press, 1952.
- ↑ 8.0 8.1 8.2 Chopra, R. Glossary of Indian Medicinal Plants. Council of Scientific and Industrial Research, New Delhi, 1986.
- ↑ 9.0 9.1 Kunkel, Günther. Plants for Human Consumption. Koeltz Scientific Books, 1984.
- ↑ 10.0 10.1 Manandhar, Narayan. Plants and People of Nepal. Timber Press, 2002.
- ↑ 11.0 11.1 Cribb, Alan and Joan Cribb. Wild Food in Australia. Fontana, 1976.