OT again. I grew one in a pile of left over builders sand in my Ceduna garden. I planted about 6 seeds after duly nicking them and soaking them.
However the survivor flowered for more than a year, with just the normal watering. I never fertilised it because I was worried it might die if over-fed. It's a desert pea after all.
The Cape is a beautiful place, as is 80 Mile, and a few other spots up that way. Safe and happy travels.