If you see a blue rose, then it has been dyed. If you get a red rose for Valentines Day, it probably doesn't smell like roses used to- "there is a trade-off between the energy that plants spend on making the complex, volatile chemicals that attract women and insects alike, and that available for making and maintaining pretty-coloured petals. So, by artificially selecting big, long-lasting flowers, breeders have all but erased another desirable characteristic."
Now, through the wonders of genetic modification, Yoshi Tanaka of Suntory has engineered a blue rose that should be a hot item in 2010. Others are figuring out how to adjust the smells: "Dr Dudareva is measuring how quickly the enzymes in scent-production pathways work, in order to identify bottlenecks and thus places where her metabolic-engineering efforts would best be concentrated."