Blue rose

Since roses lack a gene to create delphinidin, the primary plant pigment that produces true blue flowers, blue roses were usually created by dyeing white roses. So-called "blue roses" have been breed by conventional hybridization methods, but the results, such as "Blue Moon" are more precisely described as lilac in color. However, after 13 years of joint research by an Australian company Florigene, and Japanese company Suntory, a blue rose was formed in 2004 by 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 very dark mauve plant, with only trace amounts of cyanidin.

Blue roses conventionally signify mystery or attaining the impossible. They are supposed to be able to grant the owner youth or grant wishes. This symbolism derives from the rose's meaning in the language of plants common in Victorian times.