In researching I've found that the American Rose Society (www.ars.org), keeper of the world's rose knowledge, divides rose colors into 18 color classes. Every rose fits into one of these categories.

Hybridizers have just about given up on a black rose because the dark tissue of the petals absorbs so much heat that the flower dies before it opens.

There are three elements that contribute to a rose's color:

• BRIGHTNESS: This term refers to the clarity and vividness of the color, and the absence of cloudiness or muddiness.



• HUE: This component gives visual impact to the eye and distinguishes one color from another.



• CHROMA: The purity and intensity of the hue is called the chroma. Ideal chroma has virtually no gray or white in the hue.