Tint frosting green. Place cone on a 9-in. plate; frost the sides and top of cone. Starting at the bottom, alternate peppermint and spearmint candies around the cone in a single row. Alternate red and green gumdrops in a row above candies.
Arrange remaining candies in rows around the cone until reaching the top. Position a mint candy on the tip of the cone; top with a gumdrop.