I need to make a birthday cake using whipped cream frosting and decorating with sunflowers. I was going to make royal icing sunflowers, however, I was concerned that they would not hold up because of the moisture in the frosting. Would it be better to make fondant sunflowers?

AYou don't want to just pipe them?

I think fondant would be better. I don't think royal would hold up at all.

Royal icing will definitely dissolve on top of whipped cream! Fondant will melt out too. If you use dark colors they'll bleed into the whipped cream. I'd pipe my design in buttercream, chill it and place it on the whipped cream.