The quest for blue blooms: Scientists can finally celebrate with first blue chrysanthemums

For centuries, hobbyist and commercial plant breeders have sought out and selected for blue flowers. So rare are naturally blue blooms that florists go to great lengths to meet demand, including dyeing and airbrushing petals.

Fortunately for flower fans, the exclusive club has gained a new member today. After thirteen years of research, a Japanese team has unveiled the world’s first blue chrysanthemums through genetic modification of petal pigments.

The flowers won't be commercially available for some time, but local gardeners and florists are already taking notice.

Emily Neubauer, who owns the Milwaukee flower shop Belle Fiori Ltd. said local reaction could be mixed.

"I think I would have customers who would really love it because they want that control and they want that flower for a specific occasion. And then I would have other customers that want Mother Nature to do her thing."

By some accounts, fewer than 10% all flowering plants yield blue flowers, and options for florists are even more limited due to the need to propagate and harvest flowers quickly.

Chrysanthemums are one of the best-selling flowers in the world, and it’s easy to see why. These cheerful, hardy blooms are equally pleasing in a garden or a vase and come in a variety of sizes, shapes and colors.

However, producing a blue flower is no easy task. Traditional breeding methods failed to generate blue versions of many popular flowers because these species lack the ability to make the necessary pigments. In many cases, flowers described as "blue" still retain hints of purple.

To make matters more complicated, pigments found in truly blue flowers typically require metal ions such as aluminum or magnesium, multiple pigments or certain levels of acidity to properly turn them to the color that we see.

In more recent decades, scientists have used genetic engineering to try to breed new blue flowers. In 2004 the Japanese company Suntory announced that it had generated the first blue roses by inserting genes from pansies. Though the new roses produced almost 100% of the desired blue pigment, called delphinidin, their colors were still limited to mauve and lilac.

The problem occurred because delphinidin shifts its color depending on the acidity of its environment. True blue remained elusive because the rose petals were too acidic, causing the delphinidin to appear redder. Changing the acidity was not an option, as it would detrimentally affect the health of the flower.

In contrast to roses, chrysanthemums were able to yield a truer blue partly because they are weakly acidic, said Naonobu Noda, the lead author on the paper describing the new flowers.

For the chrysanthemum project, researchers from the Japanese National Agriculture and Food Research Organization and Suntory chose a specific version of delphinidin found in the vividly blue flowers of the butterfly pea.

The first gene added came from another popular garden flower, Canterbury bells. This gene converted a naturally occurring red pigment in chrysanthemums to delphinidin.

Next, a gene from the butterfly pea attached two sugar molecules to the delphinidin. Researchers had planned to perform further modifications to complete the butterfly pea pigment, but surprisingly only the first two genes were needed to produce blue chrysanthemums.

Noda said this result was particularly unexpected because prior studies had shown that the attachment of the sugars produced red coloration. Additional study of the blue chrysanthemums revealed that the observed color was in fact due to the combined effects of delphinidin and a class of copigments called flavones that are commonly found in flowers.

While this method may open the way to producing more species of blue flowers, consumers will have to wait to buy bouquets of their own.

Before they can be sold to the public, additional research is required to ensure that the blue chrysanthemums are sterile and cannot accidentally crossbreed with wild chrysanthemums.

“The safety of the blue chrysanthemums on people and the environment needs to be investigated in the future,” said Noda.