Hi Bronwyn, Welcome to GoY, I'm assuming that you don't have winters like here in UK, so I should imagine that you can sow anytime, Sweetpeas are as hard as nuts and will grow in the cold once germinated, as long as the roots don't freeze.

We grow them in the winter and spring here, sowing in the ground from late October through early December, or pre-germinating between layers of paper towels indoors before planting outdoors late December through January. In S. A., in the hotter northern lowlands, adding 6 months to those dates will probably do fine for you. In the cooler mountains, or southern coast, you will probably want to start them in late winter, early spring--say, late July to early September, for you.

So for the sweet peas sowing directly into the soil in
March/April will give me winter flowers and sowing them into the ground in September will give me summer flowers.? Have I got it right?

Lupine and foxgloves sow the seeds in march/April for winter annuals? What happens to the plants in the summer?

Sorry for my dumb questions but want to make sure as gardening here is very new to me.

Thanks

Sorry, Bronwyn! I just now saw that you were in Johannesburg. From what I can tell of the climate there, yes, you should be able to grow two crops of Sweet Peas. Be sure to use early flowering varieties for the ones blooming in winter--other kinds need longer days to bloom. Also, extra heat tolerant kinds would perform better in the summer. Foxgloves could be grown either as a winter annual, or--in part to full shade--as a short-lived perennial. Lupines will need part shade to be happy in the summer, though they are susceptible to powdery mildew in that exposure. In my experience, perennial Lupines ('Russel Hybrids' and their kin) make lousy winter annuals, while most of the annual species are easy that way.