Blue roses have long captured the imagination, symbolizing mystery and the unattainable. Many wonder if such a botanical marvel truly exists.
The Absence of Natural Blue
True blue roses do not occur naturally due to a specific genetic limitation within the Rosa genus. Roses lack the gene responsible for producing delphinidin, the primary blue pigment found in many other blue flowers like pansies and delphiniums. Flower colors largely stem from pigments called anthocyanins, which create a spectrum of reds, pinks, purples, and even yellows in roses.
Pelargonidin and cyanidin are the main anthocyanins present in roses, contributing to orange, red, and showy pink hues. Without the enzyme flavonoid 3′,5′-hydroxylase (F3’5’H), which is necessary for delphinidin biosynthesis, roses are biologically incapable of generating a true blue color.
Scientific Creation of Blue Roses
Given the natural absence, blue roses are primarily achieved through scientific intervention, employing both genetic engineering and artificial dyeing. A significant breakthrough came from Suntory, a Japanese company, in collaboration with Florigene, an Australian company. After years of research, they successfully engineered a rose to produce delphinidin by introducing genes from other plants, such as pansies, that possess the F3’5’H enzyme.
This genetically modified rose, named ‘Applause’ and commercialized in 2009, marked the world’s first genetically engineered blue rose. These roses are often described as lavender or pale mauve rather than a true sky blue, partly due to the acidic environment within rose petals affecting the delphinidin pigment. Another method for creating blue roses is artificial dyeing, a common practice where white roses absorb blue dye through their stems. This offers a range from light to deep blue depending on dye concentration and absorption time.
Naturally Occurring Blue-ish Hues
While true blue roses remain elusive in nature, some naturally occurring rose varieties exhibit blue-ish, lavender, or mauve tones. These colors are not true blues but rather shades of purple or grey that can appear bluish under certain lighting conditions. The color in these roses results from specific combinations of existing rose pigments, often involving a reduction in red-producing anthocyanins, which allows purple or grey undertones to become more apparent.
Examples of such varieties include ‘Blue Moon’, ‘Rhapsody in Blue’, ‘Mainzer Fastnacht’ (also known as ‘Sissi’), and ‘Indigoletta’. ‘Rhapsody in Blue’ is frequently cited as one of the “bluest” roses available through conventional breeding, displaying a blue-violet hue with a white center. These roses represent the closest nature gets to blue in the rose family.