Common Name: Rooibos

General Information

Aspalathus linearis is an erect to spreading, highly variable shrub growing up to 2 metres tall[].
The plant is the source of rooibos tea and is both harvested from the wild and cultivated on a commercial basis in S. Africa - the tea is sold worldwide. This is one of the few wild species to have been developed as a commercial crop in the 20th century[]. It is grown both for use as a refreshing, caffeine-free tea, and also for its purported medicinal benefits[].

Known Hazards

None known

Botanical References

Range

S. Africa - south and south-west Cape.

Habitat

Sandy hills and on the sides of mountains[]. Well-drained, sandy but moisture-retaining, non-acidic soils[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Shrub
Height	1.50 m
Pollinators	Insects
Cultivation Status	Cultivated, Wild

Cultivation Details

Aspalathus linearis grows in a winter-rainfall area of southern Africa with a Mediterranean-type climate. It experiences cold, wet winters with frosts, and hot, dry summers; the mean annual rainfall is in the range 300 - 350mm[]. Although it tolerates several degrees of frost in its native habitat, it also needs hot, dry summers for its wood to ripen properly and thus make it more cold tolerant. In temperate regions, such as Britain, where the summers tend to be cooler and moist it becomes much more susceptible to winter damage and so is more likely to be grown in a pot and overwintered under protection[].
Requires a very well-drained acid sandy soil and a warm sunny position[]. Succeeds in poor soils[]. When grown in pots it needs to be kept dry but not arid in the winter[].
Commercial plantations are harvested annualy, they last for about 5 - 7 years before they need to be replaced[].
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[].

Edible Uses

A tea made from the dried fermented leaves tastes similar to oriental tea made from Camellia sinensis[]. It is less astringent, however, due to the lower tannin content[]. It is caffeine-free, but has a higher content of fluoride which might help to protect against tooth decay[]. Recent research has shown that this tea contains a substance similar to superoxide dismutase, an antioxidant compound that is thought to retard the ageing process[].
An environmentally friendly way of harvesting the tea can be used that involves cutting only the young branches. Once they are cut, they are neatly bound and transported to the process yards. The older branches are left on the tree and the bushes get slightly taller every year. The tea cuttings are chopped very fine and then bruised to ensure that the important chemical reaction which develops the characteristic colour and flavour of the tea can take place. After watering and airing, the tea is left to 'sweat' in heaps and it at this point that the tea acquires its typical reddish brown colour and develops its sweet flavour. After the sweating process has been completed, it is spread out in a large drying yard to dry in the sun[].

The leaves are sometimes used as a flavouring in foods and in baking[].

Medicinal

Rooibos was traditionally used by the Bushmen and Hottentots of South Africa and is becoming increasingly popular in the West as a pleasant tasting tea that also has health benefits[].
A tea made from the leaves and stems of rooibos is generally beneficial to the digestive system and relaxes spasms[], it has been used in the treatment of vomiting, diarrhoea and other mild gastric complaints[]. It has also been shown to be of benefit when used internally and externally in the treatment of a wide range of allergies especially milk allergy[], eczema, hay fever and asthma in infants[].

Other Uses

The plant is used as an ingredient in cosmetics[].

Propagation

Seed - sow late spring in a greenhouse covering the seed with about 10mm of soil[, ]. The seed has a hard seedcoat and, unless sown fresh before the seedcoat hardens, may benefit from scarification before sowing in order to speed up and improve germination. This can usually be done by pouring a small amount of nearly boiling water on the seeds (being careful not to cook them!) and then soaking them for 12 - 24 hours in warm water. By this time they should have imbibed moisture and swollen - if they have not, then carefully make a nick in the seedcoat (being careful not to damage the embryo) and soak for a further 12 hours before sowing. Prick out the seedlings into individual pots of well-drained sandy soil as soon as they are large enough to handle. Grow them on in the greenhouse for at least their first winter and plant them out in late spring or early summer after the last expected frosts. It will probably be wise to give the plants protection from the cold and from excessive rain for at least their first winter outdoors.
Cuttings of half-ripe wood in a closed frame in early summer[].