Why is the color blue so rare in nature?,
continued"When you see a blue flower — for instance, a cornflower — you see the cornflower as blue because it absorbs the red part of the spectrum," Kupferschmidt said. Or to put it another way, the flower appears blue because that color is the part of the spectrum that the blossom rejected, Kupferschmidt wrote in his book, which explores the science and nature of this popular hue.
In the book "Blue," writer Kai Kupferschmidt explores the science behind this elusive color. (Image credit: Courtesy of The Experiment)In the visible spectrum, red has long wavelengths, meaning it is very low-energy compared with other colors. For a flower to appear blue, "it needs to be able to produce a molecule that can absorb very small amounts of energy," in order to absorb the red part of the spectrum, Kupferschmidt said.
Generating such molecules — which are large and complex — is difficult for plants to do, which is why blue flowers are produced by fewer than 10% of the world's nearly 300,000 flowering plant species. One possible driver for the evolution of blue flowers is that blue is highly visible to pollinators such as bees, and producing blue blossoms may benefit plants in ecosystems where competition for pollinators is high, Adrian Dyer, an associate professor and vision scientist at the Royal Melbourne Institute of Technology in Melbourne, Australia, told the Australian Broadcasting Company in 2016.