Hopefully Cameron will chime in if he isn't too busy getting ready for his trip since this is an area he is becoming an expert on. My guess is Polyxena ensifolia, syn. Lachenalia ensifolia. It has a wide distribution that covers this area and blooms April to June. The Encyclopedia of Cape Plants says clay or granite flats so that's not quite right. Massonia jasminiflora is an Easterm Cape species. I'm quite fond of the Polyxenas which are now considered Lachenalias by some. Mary Sue