My D. capensis flowered some time ago, and, although the seeds
haven't ripened yet, it's proven to be very self-fertile; every
flower bud is ripening with seeds. Unfortunately flowering left it
weak and very susceptible to a double attack of aphids and whitefly,
which I got rid of, but it's still recovering slowly.
I've also got a D. capensis "narrow leaf" which is also getting ready
to flower. I hope it's just as fertile.