1. Spray an 8 or 9 inch springform pan. Mousse: put condensed milk, lemonade, & food coloring if using, in a large bowl. Stir with a rubber spatula until well mixed. Add a large spoonful of whipped topping, stir until blended. Fold in remaining topping.
2. Cut pound cake in half, and then cut each half until you have 16 slices. Cut each half diagonally. Fit half of the triangles in the bottom of the pan. Remove 2/3 cup of mousse & put in an air tight container. Spread 1/2 of remaining mousse evenly over triangles. Repeat layer. Cover pan & refrigerate until mousse is firm, 8 hours or overnight.
3. Flowers: roll gum drops on a sugared surface [wax paper]. Cut with a cutter, or make flowers with scissors. Add a drop of icing or other gum drop for center. 2 hours before serving, remove sides of pan, & frost sides. Add flowers & leaves.