I just put fondant roses on a buttercream cake and it is in the frige to be delivered tomorrow.

Have I just made a grave mistake?

If I take the roses off it won't be pretty, the buttercream is pretty soft.

I used sugarshacks buttercream and it doesn't seem to harden at all. Is that normal?

I've done that several times and didn't have a problem with the roses melting or flopping but I didn't use the same buttercream recipe you did. Mine is the shortening ,powder sugar, water, flavoring recipe.