Green rooibos are the unfermented leaves of the South African Rooibos bush. Rooibos only turns red when it is fermented. That process also causes the smell and taste of the leaves to changet.
Green rooibos has not had a fermentation step. Green rooibos is steamed immediately after picking. The steam prevents the chance of fermentation and oxidation and therefore the leaves retain their green colour! Green rooibos is not heated above 42ºC during steaming, so green rooibos is considered raw food.