Plan on making a cake that I want to attach a flower to the side of it like this - http://cakecentral.com/tutorial/petal-cake
I've made large flower before and had a hard time getting them to stay on the side like that, I would always have to put them on the bottom so they had something supporting them.
Thanks in advance!
I would make the flower on a wire, or a toothpick/skewer.
Make the center of the flower first and stick a skewer in it. Let it dry. Then make the flower and slide the skewer through the middle. You can attach it with royal icing. Dry in a flower former over a glass so that the skewer is hanging down in the glass. When attaching to the cake paste the bottom/back of the flower with royal icing and slide the skewer into the cake
You can also use melted chocolate to adhere it to the cake.