I've got a wedding cake due in October and the bride is making a fake flower arrangement for the top tier. How do I attach it to the top tier?
Wooden skewers down into the cake, and up into the arrangement.
You'll want to put something down under it as well, so they don't touch the icing.
Or you could go and buy a flower pick/cake pick from your supplier and insert the flower stems into that - and then gently push that into your top tier.
Or insert the pick first and then pop the flower stems in...
That way you know that everything touching the actual cake is foodsafe.