I have seen tons of these large cascading rose wedding cakes lately. It is usually 3-4 tiers, white with one large white rose that cascades over the whole cake staring mid-height of the cake. I have only seen this done on fondant cakes....can it be done on buttercream cakes with fondant rose and petals?
I would assume that as long as you can "glue" the fondant petals to the buttercream cake, it should work just fine. How do you usually adhere your fondant to your buttercream? I would worry if it gets too warm and the buttercream starts to sag that the weight of the petals might make it sag as well. I've never had this issue but just in case :) Happy caking!
Below is the link to one that I did this summer. The rose and petals are fondant on a buttercream cake. I attached them with piping gel and had no problem. I have also used water to attach fondant pieces to a buttercream cake. I have had good luck with both. The picture is also in my gallery.