I'm making my sister's wedding cake in October. I live in South Australia. She lives in Nth Qld. I'm doing dozens of Casablanca Lilies and orchids. I'm very worried about the flowers all drooping and melting in the tropical humidity when I get there. I can store them with a moisture absorber until I set them up for the wedding. But after that I don't know.
Is there a way to stop this? How do cake decorators avoid the problem in the tropics?

Make them from gumpaste, not fondant. And let them dry for months. Or simply buy them. The premade ones are hard as anything.

Thanks for your suggestions leah_s, but actually I've been decorating cakes for 20yrs and have never ever used fondant for flower making. I didn't know it was possible to do so. But I have lost gumpaste flowers to moisture before, even ones that have been boxed for over a year. This is why I am worried.
Oh, and I don't buy flowers if I can make them myself. I'd rather take the credit for the work myself lol.