True Roselle is Hibiscus sabdariffa L. (family Malvaceae) and there are two main types. The more important economically is H. sabdariffa var. altissima Wester, an erect, sparsely-branched annual, which grows to about 16 feet high. It 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.
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.
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.
In 1920, 3 new varieties of Roselle, having edible cultivars, were named: 'Rico,' 'Victor,' and 'Archer.'
Roselle succeeds best in tropical and subtropical regions from sea-level up to 3,000 feet, with a rainfall of about 72 inches during the growing season. Where rainfall is inadequate, irragation has given good results. It can be grown as a summer crop in temperate regions.
Seedlings may be raised in nursery beds and transplanted when 3 to 4 inches high, but seeds are usually set directly in the field, 4 to 6 to a hill, the hills 3 to 6 feet apart in rows 5 to 10 feet 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.
Post-Harvest and Packing
For herbage purposes, the plants may be cut off 6 weeks after transplanting, leaving only 3 to 4 inches 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 the hand. Tehy 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.