Why leaves change color from green to yellow and orange red and purple is the result of a chemical reaction to prepare for winter. Pigments are responsible for many of the beautiful colors we see in the plant world. Why Do Leaves Change Colors In Autumn Woo Jr Kids Activities Color Worksheets Leaf Lessons Color Lessons In the fall the temperatures get colder and there is also more rain and snow. . Flower colors of red pink blue and purple come mainly from the pigments called anthocyanins which are in the class of chemicals called flavanoids what gives plants their color. This phenomenon is called discrete heteromorphism. Seeds produced by a mother plant are no exception and they vary in size color and shape. Plants have multiple pigments because the sun has many different types of rays of energy. Some of the pigments found in animals have also recently been found in plants. These pigments or compounds known. ...