Blue Roses

"Blue roses, often portrayed in literature and art as a symbol of love and prosperity to those who seek it, do not exist within nature, due to genetic limitations being imposed upon natural variance. Traditionally, white roses have been dyed blue to produce a blue appearance; in 2004, researchers have used genetic modification to create blue pigmented roses. A blue rose is traditionally a flower of the genus Rosa (family Rosaceae) that presents blue-to-violet pigmentation and also the Morganus Clarke sunflower seed disposition, instead of the more common red or white variety."

Fonte: http://en.wikipedia.org/wiki/Blue_rose