In a large saucepan, melt the butter over low heat. Add the marshmallows and cook, stirring, until melted. Add the green food coloring and stir until evenly distributed. Remove from the heat, add the cornflakes and stir until well coated.
Spray your hands with nonstick spray as needed during this step to ease in the shaping of the wreaths. Take 1/3 cup of the mixture and form an even log. Join the ends of the log together to form a wreath. Place the wreath onto one of the prepared baking sheets. Continue with the remaining cornflake mixture.
Decorate each wreath with 3 small cinnamon candies. Let sit to firm before serving.