Rainbow roses feature a beautiful mix of vividly colored petals on each bloom and they are not artificial.
The rainbow rose is a rose that has had its petals artificially colored. The method exploits the rose natural processes by which water is drawn up the stem. By splitting the stem and dipping each part in different colored water, the colors are drawn into the petals resulting in a multicolored rose. With these changes to the rose, it causes them to not live as long as an uncolored rose. The colors are artificial. Besides roses, other cut flowers like the chrysanthemum, carnation, hydrangea, and some species of orchids can also be colored using the same method.
The uncomplicated process has been known for more than a millennium. Several companies have moved to patent the process. It appears they have been partially successful. It will be up to the courts to decide if the process can be patented.
The Original Rainbow Rose has the seven colors of the rainbow and is the most popular rose in this category. However, there is also the tropical variant with combinations of red/pink and yellow, and the ocean variant with combinations of green and blue. Other color combinations are also possible, though black and white are impossible to make.