We used 2 types of icing, buttercream and royal icing Buttercream is the soft stuff that we used to ice and decorate. Royal icing is what we made all the flowers from. Royal icing hardens and then you can lift and place the flowers on the cake as desired.
Buttercream Icing: Annabelle's Recipe
1 cup shortening
2 tbsp milk or water
1 tsp of butter vanilla flavoring
1/2 tsp of creme bouquet flavoring
1 lb of confectioners sugar
Mix the shortening, milk/water, and flavors in a mixer with the paddle attachment until it becomes creamy. Then add the powdered sugar. If you want the icing creamier add more milk/water, if you want it stiffer add more sugar.
Annabelle told us to use Walmart's generic shortening because Crisco has removed the trans fat from their shortening which makes it not hold up as well when used for decorating. Using butter actually tastes better, but when it comes to decorating, the shortening is easier to work with.
Buttercream can be used for all decorating including roses. I would recommend the royal icing for the small or intricate flowers, like the ones I did on the hat cake.
Royal Icing for making flowers: Recipe from the Arteco
1/4 cup meringue powder
1/2 cup water
4 cups of sifted powdered sugar
Beat the water and powder until it peaks, then add powdered sugar. I had to add another cup of powder sugar to get the icing stiff enough to work with.