Rooibos belongs to the genus Aspalathus and is part of the legume family (FABACEAE). This genus has over 200 species and is indigenous to South Africa. Only the Aspalathus linearis species (Rooibos) has economic value.
The plant is a shrub-like bush with a central, smooth-barked main stem. Near the soil surface the stem subdivides into a number of strong offshoots, followed by delicate side branches each bearing, singly or in clusters, soft, needle-like leaves.
The plants' height at maturity varies from 1 to 2 metres in its natural state, while the height of cultivated plants varies from 0,5 to 1,5 metres, depending on the age of the plant, as well as the climate and soil conditions in the area of production. Rooibos is grown at a varying altitude of approximately 300 to 600 metres above sea level.
The Rooibos plant has adapted well to the harsh conditions of the Cederberg region where temperatures drop to zero degrees centigrade during the winter months and rise to a blistering 48 degrees centigrade in summer.
The winter rains vary between 180 mm to 500 mm per annum. No irrigation is used and the Rooibos plant is often subjected to severe drought conditions. The survival mechanism of this hardy bush is its tap root that digs down 3 metres or more into the well-drained, cool, sandy soil that has a high acidity level.
Although the plant requires a production area with winter rainfall, its active growth only starts in spring, increasing towards midsummer after which growth declines. During October the plant is covered with small, yellow flowers. Each flower produces only one small pod containing a single, very small, light yellow, hard-shelled, dicotyledonous seed.
Seeds are collected by sifting the sand around the plants. The seeds are scrubbed with mechanical scourers to increase the germination potential from 30% to about 95%.