I think that you made a mistake in putting this question in the Physics category but anyway..... . There are multicolor roses. There are white roses which are pink at the edge of the petal. I have a climbing rose at my front door that is cream yellow and fades to peachy pink in the center. The color of these roses changes slightly with the weather. They are more peachy when it is warmer.. . At the base of all this is the same mechanism that makes your eyes brown or blue, genetics.