In this green icing color mixing demo I make green buttercream frosting with only yellow and blue, which are the two primary colors that make green. If you don't have green food coloring, you can still achieve green with primary colors, and you'll learn how to make green color icing with basic food coloring here. This is a basic spring green, and you'll see how to adjust the color to make a citrus green that's more yellow for your cake decorating designs.