Place cookies, flat-side up, on a tray. Microwave white chocolate chips in small microwavable bowl on HIGH 30 seconds or just until melted. Stir until completely melted and smooth. Spoon into small resealable plastic bag. Snip a small corner from bag. Pipe a dot of white chocolate on edge of each cookie. Place pretzel stick on dot of chocolate to form the stem of the flower. Pipe a second dot of chocolate on pretzel stick above the first dot. Refrigerate 5 minutes or until chocolate is set.
Meanwhile, tint 1 1/4 cups of the frosting grass green, using 9 drops yellow Food Color and 5 drops green Food Color. Divide remaining frosting into 3 small bowls. Tint each bowl a different color with: 5 drops yellow Food Color, 3 drops NEON blue Food Color, 3 drops red Food Color. Spoon each color frosting into separate small resealable plastic bags. Place coconut in resealable plastic bag. Add 5 drops green and 9 drops yellow Food Color to coconut in bag; shake until coconut is evenly tinted.
Spread top of each cupcake with grass green frosting. Roll the edge of each cupcake in tinted coconut.
Snip a very small corner from each bag of tinted frosting. Pipe frosting over the cookies in a flower design. Add a candy-coated chocolate to the center of each flower. Insert 2 cookie flowers into each cupcake at different heights. Cut the gumdrop leaves in half lengthwise. Insert the leaves into the cupcakes at the base of each flower.