Namaqua land Flowers or west coast flowers season in the West Coast National Park is at its peak from August to September annually. There is a lot about it on the Web - google West Coast Flowers for a better overview.
One of my friends is BIG into photographing Fynbos specifically and joins a group of knowledgeable people, botanists and authors on the subject, almost on a weekly basis - especially in season, to hunt down flowers and plants. In fact he recognised a new one last year which has now been described. One can enter the park for a day - probably an hour and a half from Cape Town - but there is much more than just the park. There is also table mountain and other areas with fynbos.
Any questions I can answer - let me know.
oh we also have Kirstenbosch Botanical Gardens - in Cape Town - world class