Source: Sub-Tropical Fruit Club of Qld
The qualities of the Rosella (Hibiscus sabdariffa L. Malvaceae) (otherwise known as roselle or Jamaican Sorrel) are not well known by many home gardeners. Rosella may be considered a bit of a novelty for jam-making, but its other qualities and uses are not well appreciated. As we have found out this summer, the rosella can be used for much more than the traditional jam or jelly. Its flavour as a stewed fruit is superb – something like rhubarb, with a hint of cranberry and plum. It is delicious with yoghurt or ice-cream. Add to this the fact that rosella is hardy and easy to grow, productive, perfectly adapted to a subtropical climate, and you have a perfect garden fruit for South East Queensland.
Rosella is an annual member of mallow family, growing in warm temperate to tropical areas. Sow in spring, mature after 9 weeks. Rosella is an erect, bushy, herbaceous shrub which can grow to heights of 2 m. It is a short-day plant and photoperiodic, which means that it won’t begin flowering until the days are shortening. In South East Queensland, plant in spring, and flowering will start in January – February, with harvest from March – May. Harvesting causes latent buds to develop and extends the flowering life of the plant. It is native from India to Malaysia, where it is commonly cultivated, and is now common in Africa, the Tropics and Subtropics of both hemispheres, and in many areas of the West Indies and Central America has become naturalised.
There is also a native rosella H. heterophyllus which is found all along the east coast of Australia from central N.S.W. up to the Lockhart River. It is larger plant, up to 5 metres. In South East Queensland it has white flowers. Its uses are similar to the true rosella, and it has been described as a versatile vegetable, with buds that can be stewed, leaves tasting like sorrel and roots like woody parsnips (see warning below). It prefers a moist open spot but adapts to dry conditions and partial shade.
The culinary uses of rosella are based on the crimson coloured calyx – the petal-like bracts that develop around the seed buds after the flower drops, and the round green seeds buds themselves. The calyces and buds have many and varied uses. Here’s some of them:

  • stew the calyces with sugar as a dessert fruit or filling for tarts or pies
  • make sauce, juice or syrup
  • steep the calyces of 3 or 4 buds in boiling water for delicious red zinger tea
  • make jam, marmalade, relish, chutney or jelly from the calyces and buds. No pectin is needed as the calyces possess 3.2% pectin. Use with puddings, icing, or poured over pancakes, waffles or ice cream
  • cook calyces with 1:4 water in ratio to amount of calyces, and use for cold drinks. This may be frozen or bottled in sterilised, sealed bottles or jars. It keeps well providing no sugar has been added.
  • For a more zesty drink, put calyces into a jug with a little grated ginger and sugar, pour 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
  • make a colourful wine from the juice
  • The young leaves and tender stems of rosella can also be eaten raw in salads

Nutritionists have found that rosella calyces are high in calcium, niacin, riboflavin and iron. Seeds also make an good feed for chickens.
To prepare rosellas, wash and then make an incision all around the tough base of the calyx below the bracts to free and remove the base with the seed capsule attached. The calyces are then ready for immediate use and the capsule part is used whole as part of the jam or jelly recipes.
Rosellas are suitable for temperate to tropical climates with well-distributed rainfall of 1500–2000 mm yearly, from sea-level to about 600 m altitude. They tolerate a warmer and humid, but are susceptible to damage from frost. Rosellas will adapt to a variety of soils but prefer a permeable soil with humus. It is not shade tolerant. Soil preparation should be deep and thorough. Propagate from seeds and cuttings. Cuttings produce shorter plants but the yield of calyces is relatively low.
Use whatever fertilizer would be ordinarily used for vegetables. Early pruning will increase branching and development of more flowering shoots. Harvest the fruits when they reach a good size but still snap off easily by hand, The lower fruits may require cutting with secateurs.
Rosella’s major enemy is the root-knot nematode, and they should not be planted where this pest is prevalent. In Australia, 3 beetles, Nisotra breweri, Lagris cyanea, and Rhyparida discopunctulata, attack the leaves.