Preheat oven to 175 degrees. Fit pastry bag with coupler, and fill with meringue. Pipe flowers and petals onto parchment-lined baking sheets, using different tips to create a variety of shapes and sizes. (We used a leaf tip, multi-opening tip, and star tip. You will need about 16 flowers and petals per cupcake.)
Bake until meringue is dry but not brown, about 30 minutes. Let cool on parchment on wire racks.
Mound tops of cupcakes with frosting. Immediately arrange meringue flowers and petals on tops.