Roses delight us with their variety of colours, forms and perfumes, and yet there is something missing….a true blue rose. My interest in “blueish” roses probably dates form the mid 70’s when In entered the rose ‘Blue Moon’ in a Flower & Vegetable show of the Newfoundland Horticultural Society. On the Friday before the show I could only find partially opened bud in my garden, a despite using a few well known tricks like immersing it neck deep in warm water seasoned with a little added sugar, it had only by Sunday, it had blossomed forth to show all the pristine beauty that only a hybrid tea rose can. By then the ‘Best Rose in the Show’ had collapsed into an over-blown frumpy cluster of petals, and visitors couldn’t understand why my ‘blue’ rose had not been placed first!
Of course, ‘Blur Moon’ had to be exhibited in the ‘Any other Colour’ Section. This was not too surprising at there were relatively few ‘Blue’ roses around at that time. The introduction of the rose ‘Sterling Silver’ in 1957 had heralded a new colour-break that seemed to hold great potential, although whether you could describe tits colour as silver or light lavender was uncertain. Also it tended to fade to a dull grey, which was not too appealing, but never the less, ‘Stirling Silver’ launched an interest in breeding roses with a lavender-mauve-purple tinge that hybridizers persisted in calling ‘Blue-something’…. Like ‘Blue boy’, ‘Blue Girl’, ‘Blur Moon’, and ‘Blur Nile’. The ‘blue-myth’ was further perpetuated in catalogues; anyone who had tried to photograph a mauve-purple-hued rose knows all about the difficulties in obtaining a true representation, and the same was true for ‘blue’ roses.
Naturally the search for a blue rose became something of a ‘Holy Grail’ for both amateur and professional breeders. One amateur breeder who came quite close was Frank Cowlishaw, a retired engineer in England. After 20 years of devoted breeding Frank produced a lovely floribunda rose in 1977 he called ‘rhapsody in Blue’ (Frantasia). The gardening media heralded this achievement with “Amateur breeds blue rose”, and in fact it went on to win several prizes, including a Gold Medal at the Royal National Rose Trials in 1999, and was named “Rose of the Year” in 2003 in the United Kingdom. But sadly it was not a true-blue rose; officially the colour was described as “dark plum”, and to look “remarkably blue on an overcast day”! To some it appeared to have a vivid red-purple colour that changed to a lighter, duller purple, with age. Even Frank Admitted that it was not perfect, can that he had been trying to attain the unattainable.
Of course he was right; before the development of the biotechnology and gene transfer it was unattainable. To understand why you have to consult the roses’ genes. Roses re unable to produce a blue pigment called delphinidin, named after the blue pigment extracted form blue petals of a delphinium, it he same pigment that produces the blue pigmentation in petunia, pansy and gentian petals, but it is notably absent from roes, carnations, lilies, chrysanthemums and gerberas, which account for about 75% of the commercial cut flower trade.
Chemically it’s n anthocyanin, one of a group of naturally occurring pigments. The colours of theses pigments are determined by the number of hydroxyl groups that are added to a precursor. One extra hydroxyl group produces pelargonidin that gives some pelargoniums (Geraniums) their dark brick red colour. Adding a second hydroxyl group produces a light pink-red colour (cyanidin) and a third hydroxyl group the deep blue of delphinidin. Attachment of the third hydroxyl group requires an enzyme called flavonoid 3’5’-hyroxylase, and it is the gene that produces this enzyme that is missing in roses, as well as in carnations, chrysanthemums and gerberas.
Once this was known the race was on to isolate a ‘blue’ gene and introduce it into the petals of flowers that lack it. The Australian Calgane Pacific Biotechnology Company was the first to isolate a ‘blue’ gene in 1991 from the petals of petunia. After spending millions of dollars they obtained the first ‘transgenic’ blue flowers, by incorporating a ‘blue gene’ into a white carnation, which they called “Moonaqua”, all in different shades of mauve.
Interest then turned to developing blue roses. The Calgane company, now renamed Florigene, entered into a joint venture with Suntroy, a Japanese Beverage company, and in 2009 announced they had developed the world’s first ‘blue’ rose*. Simplistically put, they used gene silencing technology to turn off, or silence, the production of red pigment in the rose petal, then, ‘opened a door’ with a gene from a blue pansy, and used a ‘Applause’*, was first released to selected florists in Japan, and in 2011 it became available in Canada and the USA. It is considered a prototype, and although its petals are describes as “more silver-purple than sky-blue”**, its significance lies in its colour coming from a blue pigment that produced by the plant itself, rather than it being a modification of red pigments as in previous breeding attempts.
More is needed than just a ‘blue gene’ to breed an acceptable blue rose. The intensity of the blue colour is influenced by the degree of acidity of the cells in petals, as well as by the presence of other pigments, so further tinkering will be required to modify these conditions before we see a sky-blue rose in a bedding bouquet. But they are getting close, and who know, one day we might even see a true blue rose take first place in its own Blue rose section of a flower Show!
*The delphinidin pigment was inserted into Rosa ‘Cardinal de Richelieu’, a double cupped deep purple gallica rose.
**Go to http://Wierd.com/wiredscience/2011/09/blur-roses-for-sale/ for a photo of the ‘blue rose ‘Applause’.
Ian Senciall is an Honorary member of the Newfoundland Horticultural Society (NHS). He edited and co-wrote two NHS publications; ‘The Avalon Gardener’, Ian R Senciall, Betty Hall (Illustrator, William F. Matthews and Kenneth G Proudfoot (2000) and ‘The Avalon Vegetable Garden’, Ian R. Senciall and Betty Hall (Illustrator), (2005). He is retired from Memorial University Faculty of Medicine where he was a professor of Biochemistry.
Ian is also a member of the ‘John Cabot Rose society of Newfoundland.