Most Singaporeans know that the fruits that go into the making of Ribena are blackcurrants and the plant that produces them is not well adapted to grow in the tropics. Fortunately, the roselle plant is a blackcurrant plant substitute that can be grown in the lowland tropics. The roselle is totally unrelated to the blackcurrant. Botanically known as Hibiscus sabdariffa, the roselle plant is a member of the hibiscus family, Malvaceae while the other hand, the blackcurrant, Ribes nigrum, belongs to the rose family, Rosaceae.
The pink flower of the roselle plant that looks like a small hibiscus.
To make the original Ribena drink, the fruits of the blackcurrant are used but to make a beverage that tastes like Ribena from roselle, one has to use the calyces produced by a particular race of a cultivar of the roselle plant, Hibiscus sabdariffa var. sabdariffa ruber. Calyces (plural; calyx, singular) are the collections of sepals that form a structure that is found just behind the petals of each flower. Sepals in most flowers are green in colour and they form the outer protective covering of a flower bud.
The calyces of the roselle plant are relatively fleshy and they remain so during the fruit formation process. They can be harvested and used fresh, after removing the fruit capsule, to produce a rather sour drink that is deep red in colour made by boiling in water. The decoction that result needs to be subsequently sweetened by adding sugar. The beverage that best served after being chilled in a refrigerator is believed to possess anti-hypertensive, diuretic and mild laxative properties. It contains high amounts of vitamin C and anthocyanins, which are natural antioxidants. The calyces can also be picked and dried in the sun where they can then be kept in a cool and dry place for future use. In Singapore, one can easily buy large packets of dried roselle calyces in Chinese medical halls.
The calyces of the roselle plant are useful for making drinks as well as a decorative cut-flower.
The roselle plant is easily raised from seeds or stem-cuttings. They make good beginner’s plants for children who love to drink the Ribena beverage. The roselle plant needs to be grown using well-drained, fertile soil and located in an area with direct sunshine. It can be planted outdoors in the ground or inside a container placed on a sunny windowsill or balcony. Although not as showy as its ornamental garden counterparts, the roselle plant produces rather attractive, pink-coloured hibiscus-like flowers that have a distinctive eye in the center. They are transient beauties as the flowers only last for a day.
Another unnamed roselle cultivar with calyces that are larger and fleshier.
Various cultivars of the roselle plant exist and they mainly differ in terms of the size of the calyces they produce. One other use that I can think of for the roselle plant other than harvesting its calyces for making drinks is to use it as a cut-flower material. A stem that is fully laden with calcyes at every node, after being stripped of all its leaves does make an attractive display item in a flower arrangment for the dinner table.
Besides the food uses of its calyces, the young leaves and tender shoots of the roselle plant can be eaten raw in salads or cooked as greens alone or mixed with other greens or with meat or fish.
Note that the other cultivar of the roselle plant, H. sabdariffa var. altissima is cultivated for the production for bast fibre that is derived from stem of the plant and not for its calyces. The fibre may be used as a substitute for jute in making burlaps. Certain H. sabdariffa var. sabdariffa cultivars also yield fiber.
For more info, refer to this website – http://www.hort.purdue.edu/newcrop/morton/roselle.html
Mr. Albert Quek sharing his experience on D.I.Y vertical gardening to the audience. 
D.I.Y vertical wall created by Mr. Albert Quek.
