Blue roses were traditionally created by dyeing white roses, since roses lack a gene to produce delphinidin, the primary plant pigment that produces true blue
flowers. So-called "blue roses" have been bred by conventional
hybridization methods, but the results, such as "Blue Moon" are more
accurately described as lilac in color. However, after thirteen years of joint research by an Australian company Florigene, and Japanese company Suntory, a blue rose was created in 2004 using genetic engineering. The delphinidin gene was cloned from the petunia and inserted into a mauve-blend rose, the Old Garden Rose 'Cardinal de Richelieu' (a Rosa gallica). However, since the pigment cyanidin was still present, the rose was more dark burgundy than true blue. Further work on the rose using RNAi technology to depress the production of cyanidin produced a mauve colored flower, with only trace amounts of cyanidin.
Blue roses traditionally signify mystery or attaining the
impossible. They are believed to be able to grant the owner youth or
grant wishes. This symbolism derives from the rose's meaning in the language of flowers common in Victorian times.
According to a Chinese folktale, the blue rose signified hope against unattainable love. According to the Yui-Tua peoples of some pacific island groups the appearance of a blue rose signals the end of times.