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Morton, J. 1987. Roselle. p. 281–286. In: Fruits of warm climates. Julia F. Morton, Miami, FL.


Roselle

Hibiscus sabdariffa L.




True roselle is Hibiscus sabdariffa L. (family Malvaceae) and there are 2 main types. The more important economically is H. sabdariffa var. altissima Wester, an erect, sparsely-branched annual to 16 ft (4.8 m) high, which is cultivated for its jute-like fiber in India, the East Indies, Nigeria and to some extent in tropical America. The stems of this variety are green or red and the leaves are green, sometimes with red veins. Its flowers are yellow and calyces red or green, non-fleshy, spiny and not used for food. This type at times has been confused with kenaf, H. cannabinus L., a somewhat similar but more widely exploited fiber source.

The other distinct type of roselle, H. sabdariffa var. sabdariffa, embraces shorter, bushy forms which have been described as races: bhagalpuriensi, intermedius, albus, and ruber, all breeding true from seed. The first has green, red-streaked, inedible calyces; the second and third have yellow-green edible calyces and also yield fiber. We are dealing here primarily with the race ruber and its named cultivars with edible calyces; secondarily, the green-fruited strains which have similar uses and which may belong to race albus.

Vernacular names, in addition to roselle, in English-speaking regions are rozelle, sorrel, red sorrel, Jamaica sorrel, Indian sorrel, Guinea sorrel, sour-sour, Queensland jelly plant, jelly okra, lemon bush, and Florida cranberry. In French, roselle is called oseille rouge, or oseille de Guinée; in Spanish, quimbombó chino, sereni, rosa de Jamaica, flor de Jamaica, Jamaica, agria, agrio de Guinea, quetmia ácida, viña and viñuela; in Portuguese, vinagreira, azeda de Guiné, cururú azédo, and quiabeiro azédo; in Dutch (Surinam), zuring. In North Africa and the Near East roselle is called karkadé or carcadé and it is known by these names in the pharmaceutical and food-flavoring trades in Europe. In Senegal, the common name is bisap. The names flor de Jamaica and hibiscus flores (the latter employed by "health food" vendors), are misleading because the calyces are sold, not the flowers.

Roselle
Plate XXXVI: ROSELLE, Hibiscus sabdariffa
Description

H. sabdariffa var. sabdariffa race ruber is an annual, 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.

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.

Seedpods of roselle
Fig. 79: Seedpods of roselle (Hibiscus sabdariffa), enclosed in their red, fleshy, acid calyces, are piled high in the markets of Panama in January.

Origin and Distribution

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.

The Flemish botanist, M. de L'Obel, published his observations of the plant in 1576, and the edibility of the leaves was recorded in Java in 1687. Seeds are said to have been brought to the New World by African slaves. Roselle was grown in Brazil in the 17th Century and in Jamaica in 1707. The plant was being cultivated for food use in Guatemala before 1840. J.N. Rose, in 1899, saw large baskets of dried calyces in the markets of Guadalajara, Mexico.

In 1892, there were 2 factories producing roselle jam in Queensland, Australia, and exporting considerable quantities to Europe. This was a short-lived enterprise. In 1909, there were no more than 4 acres (1.6 ha) of edible roselle in Queensland. A Mr. Neustadt of San Francisco imported seeds from Australia about 1895 and shared them with the California State Agricultural Experiment Station for test plantings and subsequent seed distribution. It was probably about the same time that Australian seeds reached Hawaii. In 1904, the Hawaiian Agricultural Experiment Station received seeds from Puerto Rico. In 1913 there was much interest in interplanting roselle with Ceara rubber (Manihot glaziovii Muell. Arg.) on the island of Maui and there were some plantations established also on the island of Hawaii, altogether totaling over 200 acres (81 ha). The anticipated jelly industry failed to materialize and promotional efforts were abandoned by 1929.

P.J. Wester believed that roselle was brought to Florida from Jamaica about 1887. Plants were grown by Dr. H.J. Webber at the United States Department of Agriculture's Subtropical Laboratory at Eustis, Florida, in the early 1890's, but all the roselle was killed there by a severe freeze in 1895. Cook and Collins reported that roselle was commonly cultivated in southern Florida in 1903. In 1904, Wester acquired seeds from Mr. W.A. Hobbs of Coconut Grove and planted them at the United States Department of Agriculture's Subtropical Garden in Miami. He was enthusiastic about roselle's potential as a southern substitute for the cranberry. In 1907, he stated that the fresh calyces were being sold by the quart in South Florida markets. He introduced 3 edible cultivars into the Philippines in 1905. In 1920, he declared: "No plant that has ever been brought into the Philippines is more at home and few grow with so little care as the roselle, or are so productive. Still, like so many other new introductions, the roselle has been slow to gain hold in the popular taste though here and there it is now found in the provincial markets. "

In 1928, Paul C. Standley wrote: "roselle ... is grown in large quantities in Panama, especially by the West Indians. So much of the plant is seen in the markets and on the roads that one would think the market oversupplied." This situation has not changed. I saw great quantities of the whole fruits and the calyces in Panama markets in January of 1976.

Roselle became and remained a common home garden crop throughout southern and central Florida until after World War II when this area began to develop rapidly and home gardening and preserving declined. Mrs. Edith Trebell of Estero, Florida, was one of the last remaining suppliers of roselle jelly. In February, 1961, I purchased the last 2 jars made from the small crop salvaged following the 1960 hurricane and before frost killed all her plants.

In 1954, roselle was still being grown by individuals in the Midwest for its edible herbage. By 1959 and 1960, when there was widespread alarm concerning coal-tar food dyes, it was easy to arouse interest in roselle as a coloring source but difficult to obtain seeds in Florida. At that time, I purchased them from Gleckler's Seedsmen in Metamora, Ohio. Roselle had by then become nearly extinct in Puerto Rico also. From time to time over the next dozen years I was able to obtain a few seeds from old timers in Central Florida. In 1973, roselle was featured in the catalog of John Brudy's Rare Plant House, Cocoa Beach (now John Brudy Exotics, Brandon, Florida and no longer listing the seed). Reasoner's Tropical Nurseries in Bradenton was selling plants in containers and giving to purchasers a sheet of recipes. From Lawrence Adams of Arcadia, I obtained seeds which came from the Virgin Islands where this particular strain is said to mature its fruit a month early. These seeds and seeds purchased by John G. Dupuis, Jr., from Brudy were the basis of a large planting at DuPuis' Bar D Ranch in Martin County. Many packets of seeds were distributed to home growers during the following winter.

Today, roselle is attracting the attention of food and beverage manufacturers and pharmaceutical concerns who feel it may have exploitable possibilities as a natural food product and as a colorant to replace some synthetic dyes.

In 1962, Sharaf referred to the cultivation of roselle as a "recent" crop in Egypt, where interest is centered more on its pharmaceutical than its food potential. In 1971, it was reported that roselle calyces, produced and dried in Senegal, particularly around Bambey, were being shipped to Europe (Germany, Switzerland, France and Italy) at the rate of 10 to 25 tons annually.

Varieties

In 1920, Wester described 3 named, edible cultivars as being grown at that time in the Philippines:

'Rico' (named in 1912)–plant relatively low-growing, spreading, with simple leaves borne over a long period and the lobed leaves mostly 3-parted. Flower has dark-red eye and golden-yellow pollen. Mature calyx to 2 in (5 cm) long and to 1 1/4 in (3.2 cm) wide; bracts plump and stiffly horizontal. Highest yielder of calyces per plant. Juice and preserves of calyx and herbage rich-red.

'Victor'–a superior selection from seedlings grown at the Subtropical Garden in Miami in 1906. Plant taller–to 7 ft (2.13 m), more erect and robust. Flower has dark-red eye and golden-brown pollen. It blooms somewhat earlier than 'Rico'. Calyces as long as those of 'Rico' but slenderer and more pointed at apex; bracts longer, slenderer and curved upward. Juice and preserves of calyx and herbage rich-red.

'Archer' (sometimes called "white sorrel") resulted from seed sent to Wester by A.S. Archer of the island of Antigua. It is believed to be of the race albus. Edward Long referred to "white" as well as red roselle as being grown in most gardens of Jamaica in 1774. Plant is as tall and robust as 'Victor' but has green stems. Flower is yellow with deeper yellow eye and pale-brown pollen. Calyx is green or greenish-white and smaller than in the 2 preceding, but the yield per plant is much greater. Juice and other products are nearly colorless to amber. Green-fruited roselle is grown throughout Senegal, but especially in the Cape Vert region, mainly for use as a vegetable.

Another roselle selection which originated in 1914 at the Lamao experiment station and was named 'Temprano' because of its early flowering, Wester reported as no longer grown, the plant being less robust and less productive than the others.

A strain with dark-red, plump but stubby calyces (the sepals scarcely longer than the seed capsule) is grown in the Bahamas.

Climate

Roselle is very sensitive to frost. It succeeds best in tropical and subtropical regions from sea-level up to 3,000 ft (900 m) with a rainfall of about 72 in (182 cm) during its growing season. Where rainfall is inadequate, irrigation has given good results. It can be grown as a summer crop in temperate regions. The fruits will not ripen, but the herbage is usable.

Soil

While deep, fairly fertile sandy loam is preferable, roselle grew and produced well over many years in the oölitic limestone of Dade County. Wester observed that the high pinelands were far more suitable than low-lying muck soils. The plants tended to reseed themselves and on some properties they spread so extensively they became a nuisance and were eradicated.

Propagation

Roselle is usually propagated by seed but grows readily from cuttings. The latter method results in shorter plants preferred in India for interplanting with tree crops but the yield of calyces is relatively low.

Culture

Seedlings may be raised in nursery beds and transplanted when 3 to 4 in (7.5-10 cm) high, but seeds are usually set directly in the field, 4 to 6 to a hill, the hills 3 to 6 ft (0.9-1.8 m) apart in rows 5 to 10 ft (1.5-3 m) apart. When 2 or 3 leaves have developed, the seedlings are thinned out by 50%. If grown mainly for herbage, the seed can be sown as early as March, and no early thinning is done.

Roselle is a short-day plant and photoperiodic. Unlike kenaf, roselle crops cannot be grown successively throughout the year.

If intended solely for the production of calyces, the ideal planting time in southern Florida is mid-May. Blooming will occur in September and October and calyces will be ready to harvest in November and December. Harvesting causes latent buds to develop and extends the flowering life of the plant to late February. When the fruit is not gathered but left to mature, the plants will die in January.

Rolfs recommended whatever fertilizer would be ordinarily used for vegetables but warned that only 1/4 to 1/2 the usual amount should be applied. He wryly remarked: "As a whole, the plants are rather more vigorous than need be; consequently no attention need be paid in the direction of vigor." An excess of ammonia encourages vegetative growth and reduces fruit production. Commercial fertilizer of the formula 4-6-7 NPK has proved satisfactory.

Weeding is necessary at first, but after the plants reach 1 1/2 to 2 ft (45-60 cm) in height, weeds will be shaded out and no longer a problem. Early pruning will increase branching and development of more flowering shoots.

Harvesting

For herbage purposes, the plants may be cut off 6 weeks after transplanting, leaving only 3 to 4 in (7.5-10 cm) of stem in the field. A second cutting is made 4 weeks later and a third after another 4 weeks. Then the shorn plants are thinned out–2 of every 3 rows removed–and the remaining plants left to grow and develop fruit as a second product.

The fruits are harvested when full-grown but still tender and, at this stage, are easily snapped off by hand. They are easier to break off in the morning than at the end of the day. If harvesting is overdue and the stems have toughened, clippers must be used.

The fruits of roselle ripen progressively from the lowest to the highest. Harvesting of seeds takes place when the lower and middle tiers of the last of the fruits are allowed to mature, at which time the plants are cut down, stacked for a few days, then threshed between canvas sheets.

Yield

Calyx production per plant has ranged from 3 lbs (1.3 kg) in California to 4 lbs (1.8 kg) in Puerto Rico and 16 lbs (7.25 kg) in southern Florida. In Hawaii, roselle intercropped with rubber yielded 16,800 lbs per acre (roughly 16,800 kg/ha) when planted alone. Dual-purpose plantings can yield 19,000 lbs (17,000 kg) of herbage in 3 cuttings and, later, 13,860 lbs (6,300 kg) of calyces.

Pests and Diseases

Roselle's major enemy is the root-knot nematode, Heterodera rudicicola. Mealybugs may be very troublesome. In Australia, 3 beetles, Nisotra breweri, Lagris cyanea, and Rhyparida discopunctulata, attack the leaves. The "white" roselle has been found heavily infested with the cocoa beetle, Steirastoma breve in Trinidad, with a lighter infestation of the red roselle in an intermixed planting. Occasional minor pests are scales, Coccus hesperidum and Hemichionaspis aspidistrae, on stems and branches; yellow aphid, Aphis gossypii, on leaves and flower buds; and the cotton stainer, Dysdercus suturellus, on ripening calyces.

In Florida, mildew (Oidium) may require control. Late in the season, leaves on some Philippine plants have appeared soft and shriveled; and Phoma sabdariffae has also done minimal damage.

Keeping Quality

Rolfs, in 1929, reported that fresh roselle calyces, as harvested, were successfully shipped by rail to Washington for retail sale and he judged that they could stand rail transport to any markets east of the Mississippi.

calyces raw and cooked
Plate XXXVII: ROSELLE, Hibiscus sabdariffa (calyces raw and cooked)
Dried Roselle Calyces
Fig. 80: Dried roselle calyces are sold in plastic bags in Mexico, labeled "Flor de Jamaica", leading many to believe that they are flower petals. Actually, the flower falls before the red calyx enlarges and becomes fit for food use.

Food Uses

Roselle fruits are best prepared for use by washing, then making an incision around the tough base of the calyx below the bracts to free and remove it with the seed capsule attached. The calyces are then ready for immediate use. They may be merely chopped and added to fruit salads. In Africa, they are frequently cooked as a side-dish eaten with pulverized peanuts. For stewing as sauce or filling for tarts or pies, they may be left intact, if tender, and cooked with sugar. The product will be almost indistinguishable from cranberry sauce in taste and appearance. For making a finer-textured sauce or juice, sirup, jam, marmalade, relish, chutney or jelly, the calyces may be first chopped in a wooden bowl or passed through a meat grinder. Or the calyces, after cooking, may be pressed through a sieve. Some cooks steam the roselle with a little water until soft before adding the sugar, then boil for 15 minutes.

Roselle sauce or sirup may be added to puddings, cake frosting, gelatins and salad dressings, also poured over gingerbread, pancakes, waffles or ice cream. It is not necessary to add pectin to make a firm jelly. In fact, the calyces possess 3.19% pectin and, in Pakistan, roselle has been recommended as a source of pectin for the fruit-preserving industry.

Juice made by cooking a quantity of calyces with 1/4 water in ratio to amount of calyces, is used for cold drinks and may be frozen or bottled if not for immediate needs. In sterilized, sealed bottles or jars, it keeps well providing no sugar has been added. In the West Indies and tropical America, roselle is prized primarily for the cooling, lemonade-like beverage made from the calyces. This is still "one of the most popular summer drinks of Mexico", as Rose observed in 1899. In Egypt, roselle "ade" is consumed cold in the summer, hot in winter. In Jamaica, a traditional Christmas drink is prepared by putting roselle into an earthenware jug with a little grated ginger and sugar as desired, pouring boiling water over it and letting it stand overnight. The liquid is drained off and served with ice and often with a dash of rum. A similar spiced drink has long been made by natives of West Tropical Africa. The juice makes a very colorful wine.

John Ripperton of the Hawaiian Experiment Station maintained that, for jelly and wine-making, it is unnecessary to take out the seed capsule, but neglecting to do so may result in a "stringy" product which would be contaminated with the minute hairs from the surface of the capsule and these hairs are quite likely to be injurious unless carefully filtered out.

The calyces are either frozen or dried in the sun or artificially for out-of-season supply, marketing or export. In Mexico today, the dried calyces are packed for sale in imprinted, plastic bags. It is calculated that 11 lbs (5 kg) of fresh calyces dehydrate to 1 lb (0.45 kg) of dried roselle, which is equal to the fresh for most culinary purposes. However, dried calyces as sold for "tea" do not yield high color and flavor if merely steeped; they must be boiled.

For retailing in Africa, dried roselle is pressed into solid cakes or balls. In Senegal, the dried calyces are squeezed into great balls weighing 175 lbs (80 kg) for shipment to Europe, where they are utilized to make extracts for flavoring liqueurs. In the United States, Food and Drug Administration regulations permit the use of the extracts in alcoholic beverages.

The young leaves and tender stems of roselle are eaten raw in salads or cooked as greens alone or in combination with other vegetables or with meat or fish. They are also added to curries as seasoning. The leaves of green roselle are marketed in large quantities in Dakar, West Africa. The juice of the boiled and strained leaves and stems is utilized for the same purposes as the juice extracted from the calyces. The herbage is apparently mostly utilized in the fresh state though Wester proposed that it be evaporated and compressed for export from the Philippines.

The seeds are somewhat bitter but have been ground to a meal for human food in Africa and have also been roasted as a substitute for coffee. The residue remaining after extraction of oil by parching, soaking in water containing ashes for 3 or 4 days, and then pounding the seeds, or by crushing and boiling them, is eaten in soup or blended with bean meal in patties. It is high in protein.

Food Value

Nutritionists have found roselle calyces as sold in Central American markets to be high in calcium, niacin, riboflavin and iron.

Food Value Per 100 g of Edible Portion

Calyces, fresh*
Moisture 9.2 g
Protein 1.145 g
Fat 2.61 g
Fiber 12.0 g
Ash 6.90 g
Calcium 1,263 mg
Phosphorus 273.2 mg
Iron 8.98 mg
Carotene 0.029 mg
Thiamine 0.117 mg
Riboflavin 0.277 mg
Niacin 3.765 mg
Ascorbic Acid 6.7 mg

*Analyses made in Guatemala.

Leaves, fresh**
Moisture 86.2%
Protein 1.7-3.2%
Fat 1.1%
Carbohydrates 10%
Ash 1%
Calcium 0.18%
Phosphorus 0.04%
Iron 0.0054%
Malic Acid 1.25%

*Analyses made in the Philippines.

Seeds
Moisture 12.9%
Protein 3.29%
Fatty Oil 16.8%
Cellulose 16.8%
Pentosans 15.8%
Starch 11.1%

Amino acids (N = 16 p. 100 According to Busson)*

Arginine 3.6
Cystine 1.3
Histidine 1.5
Isoleucine 3.0
Leucine 5.0
Lysine 3.9
Methionine 1.0
Phenylalanine 3.2
Threonine 3.0
Tryptophan -
Tyrosine 2.2
Valine 3.8
Aspartic Acid 16.3
Glutamic Acid 7.2
Alanine 3.7
Glycine 3.8
Proline 5.6
Serine 3.5

*Calyces, fresh

The dried calyces contain the flavonoids gossypetine, hibiscetine and sabdaretine. The major pigment, formerly reported as hibiscin, has been identified as daphniphylline. Small amounts of delphinidin 3-monoglucoside, cyanidin 3-monoglucoside (chrysanthenin), and delphinidin are also present. Toxicity is slight.

Other Uses

The seeds are considered excellent feed for chickens. The residue after oil extraction is valued as cattle feed when available in quantity.

Medicinal Uses: 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.