One day in advance, make roses. Prepare royal icing recipe following recipe directions. Tint rose. Use tip 12, tip 104, flower nail, icing flower squares and rose icing to make 10 roses for each cake. Set aside to dry 24 hours.
Make flower pot cakes. Prepare batter following recipe directions. Bake according to pan package directions. Cool in pan 10 minutes on cooling grid. Invert pan onto cooling grid and allow to cool completely upside down.
Decorate flower pot. Prepare buttercream icing following recipe directions. Tint portions terra cotta and green. Use spatula and terra cotta icing to cover flower pot.
Assemble flower pot. Use a cut disposable decorating bag to pipe a mound of green icing in center of flower pot. Position roses. Use tip 352 and green icing to pipe leaves in between roses.