Green’s Dictionary of Slang

(S.Afr. drugs) very strong marijuana, with tiny red hairs.

2002		High Times 13 Dec. 🌐 One of the best-known strains coming out of the Transkei is ‘Rooibaard’ (Red Beard), a wonderfully uplifting weed with a generous covering of red hairs—hence the name.
2002		Stoners’ Dict. 🌐 Rooibaard [ZA] – Best buds with small red hairs.