I suspect they have got too cold and wet. If they are in pots bring them into a cool dry environment, shed/garage/greenhouse. Prune them too and they should recover unless the roots have rotted out.

I tried growing Osteospermum and will never do it again. They are sulky Pre-Madonnas in the garden. Everything must be just so or they won't perform. They are also called 'African Daisies' and those are the conditions you must provide for this plant - hot - dry - sunny - sandy. Cold, wet and dingy grey just won't do it for these and that's what I've been hearing about the UK lately.

I have several in dry-ish pots in the greenhouse and they will be happily flowering this summer. There are a couple that are reliably hardy in the uk but I cant remember which one it was.

I agree that they are from hotter climes but I think if you realise that in the UK they are considered as summer bedding you wont be disappointed. But being married to a true Yorkshire man [ short arms - deep pockets haha] I will usually take cuttings and overwinter them. I don't think of them as being Prima- donnas there are so many more plants that fit that category.

Had a good couple of years out of them but had a look today and they were all rotted out, so now unfortunately they are no more, thanks for the comments.

ah well as you said you had a good few years and this autumn/winter has been so wet. You'll know for next season.

I agree, same here Eileen, they are sold everywhere as summer bedding plants and New York summers are perfect for them, not so much for me, ha ha. It's back to Fire Island and a watermelon margarita. You gotta try one!