Leonotis ocymifolia has a distribution area probably split in two between the southern parts of South Africa (where it occurs mainly in the Eastern Cape) and in the north of the country (mainly Mpumalanga and Limpopo). But the habitat may also be continuous as Manning (2009) states.
The breaks of several hundred kilometres between separate distribution areas may have been bridged in one continuous area of prevalence in the past. But this does not necessarily have to be the case. Natural phenomena or human intervention sometimes play a role in introducing a plant in a new area without there ever having been a continuity in the overall habitat.
This plant also occurs in East Africa, including Kenya. The same issue regarding continuity of habitat may be worth investigating in this case.