Truly blue roses do not occur naturally due to genetic limitations, but scientific advancements have engineered roses with blue hues. This breakthrough provides the closest approximation to the mythical blue flower.
Why Natural Blue Roses Don’t Exist
Roses naturally produce a spectrum of colors, including reds, pinks, yellows, and whites. These colors are primarily determined by pigments called anthocyanins and carotenoids. However, roses lack the specific enzyme, flavonoid 3′,5′-hydroxylase (F3’5’H), which is essential for synthesizing delphinidin. Delphinidin is the anthocyanin pigment responsible for true blue and violet colors in many other flowers.
Without the F3’5’H gene, roses cannot produce delphinidin, making a naturally occurring blue rose impossible. This genetic gap means traditional breeding efforts cannot yield a true blue rose. The pigments roses do produce, such as cyanidin (red and pink) and pelargonidin (orange and red), do not combine to create a blue shade.
Early Attempts at Blue Hues
For centuries, the quest for a blue rose has captivated breeders, often called the “Holy Grail” of rose cultivation. Early attempts relied on artificial methods, such as dyeing white roses. Placing cut stems in blue-colored water or dye solutions allows the rose to absorb the dye through its vascular system, tinting the petals blue.
Traditional cross-pollination methods consistently failed to produce true blue roses due to the absence of the F3’5’H gene in the rose genome. These breeding attempts only resulted in purplish or lilac shades, such as ‘Blue Moon,’ which often appeared mauve or lilac.
The Genetically Engineered Blue Rose
Genetic engineering provided a significant breakthrough, allowing scientists to bypass the natural genetic limitations of roses. In 1990, Suntory partnered with Florigene to create a blue rose. Their research culminated in 2004 with the successful development of a genetically modified “blue” rose.
This process involved introducing the delphinidin-producing F3’5’H gene from a pansy into the rose genome. To enhance blue coloration and reduce interference from existing rose pigments, researchers used gene silencing technology to suppress the rose’s natural red-pigment-producing genes, such as dihydroflavonol 4-reductase (DFR). A modified DFR gene from iris was also introduced to facilitate delphinidin production.
The resulting rose, marketed as ‘Applause,’ is not a royal blue but exhibits a distinct lavender or mauve-blue hue. This is the closest to a true blue achieved through genetic modification. The color can be influenced by petal acidity, which can degrade the blue pigment. These genetically engineered blue roses became commercially available in Japan in 2009 and later in the U.S. and Canada.