Why Blue Flowers are Rare

Burmese plumbago (Ceratostigma griffithii)

Blue is the rarest flower color, seen on only 10 percent of the 280,000 flowering plants on Earth.

Among those who specialize in color analysis, it is sometimes claimed that, in reality, there has never been a true blue flower, nor will there ever be one. This has to do with the fact that there is no blue pigment in the plant kingdom and colors that appear to be blue are actually permutations of violet or purple.

Red plant pigments in flowers and fruit, known as anthocyanins, are modified or hacked, to use a cybersecurity term, through biochemical processes that bring on the blues, as it were, in flowers and fruit, enhancing their appeal to pollinators, as well as to birds and other animals that are attracted to blue fruit, gobble it down, and distribute its seeds.

The closest flowers to true blue are those seen on sea holly (Eryngium spp.), Himalayan poppy (Meconopsis spp.) and certain delphiniums.

Incidentally, the situation in the animal kingdom is no different. Neither blue butterflies, nor blue peacock feathers, nor blue eyes contain the smallest speck of blue pigment.

Perhaps God had a reason to withhold blue from the natural world. Maybe it was done so that anytime we wanted to see blue which, polls reveal, is the favorite color of most people, we would have to look up to a famously blue sky, toward heaven. This might engender heavenly aspirations among us and even make us long to bring heaven down to earth, transforming the physical and material world around us into a more heavenly and spiritual place where God would feel at home.

Thanks to a Japanese plant breeding project that took 13 years to produce the desired result, a version of a most popular flower was finally developed that, as determined by England’s Royal Horticultural Society, was officially blue, even if hacking was involved in its creation.

In order to qualify as authentically blue, a flower, when facing north, must meet certain blue standards as displayed on a highly nuanced color chart. The 13-year flower-in-the-making that met these standards was a chrysanthemum. This breakthrough could have major implications for the florist industry since chrysanthemums are, after roses, the most widely sold cut flowers.

The first blue chrysanthemum was created with the help of genes from purplish Canterbury bells (Campanula medium) and deep-blue butterfly pea (Clitoria ternatea), a tropical legume. The genes of these two plants were mixed together and then spliced into the DNA of Agrobacterium tumefaciens, a type of soil-dwelling bacteria that is known for its capacity to infect and alter the DNA in the nuclei of plant cells. The infecting bacteria altered the DNA of a magenta chrysanthemum, and the seeds of that plant produced the long anticipated blue flowers.

The first involves dissolving food coloring in water and having the stems of your cut flowers, which should be white, absorb the colored water. The results of this technique, however, are not impressive. There is definitely blue coloration in the flowers but it is weak and white is still plentiful in the final product.

A second technique utilizes a special powder that is dissolved in water prior to placement of the stems. Here, the results show strong sky blue flowers that are satisfying enough.

If you want to see royal blue coloration, however, you will need to utilize a third technique involving a dye into which the flowers are dipped, which has the advantage of giving you instant results. Powders and dyes for floral coloring are available in a variety of colors, and they are easily procured through internet vendors.

I was prompted to investigate the blue flower phenomenon upon noticing clusters of cobalt blue flowers recently. The flowers stood atop dark, evergreen foliage of a sub-shrub by the name of Burmese plumbago (Ceratostigma griffithii), that grows no more than 3 feet tall.

There is a ground cover dwarf plumbago (Ceratostigma plumbaginoides), albeit deciduous, that is also a worthy bloomer in dark blue this time of year. Dwarf plumbago, which only reaches 18 inches in height, has foliage that turns orange and red before dropping off in the fall. The flowers of these two plants are as true blue as any I have ever seen.

Of course, you could create a garden with nothing but blue flowers. Lobelia, in both light and dark blue (‘Crystal Palace’) cultivars, would definitely have a place of honor in such a garden, at least as an edging plant separating flower beds from sidewalks, from entryways, or from each other. Lobelia, which grows up no more than 6 inches tall, is a plant for all seasons, and you can scatter its seeds any time of the year. Certain hydrangea cultivars produce distinctively sky blue flowers, but only when aluminum sulfate is applied as a fertilizer.

When it comes to annuals, there are blue cornflowers (Centaurea cyanus) and love-in-a-mist (Nigella damascena) to consider, both of which grow easily from seed and both of which flower in white, pink and purple, but mostly in pale blue.

With a name like love-in-a-mist, you will be expecting a lot when you plant the seeds of this unusual plant and, I guarantee, you will not be disappointed. Foliage consists of thin green threads culminating in flowers that are flat, layered tiers of serrated petals. Fading flowers give way to spherical seed capsules with maroon markings that are quite decorative in their own right.

Your will get more than one crop of love-in-a-mist for the price of a single seed packet since they do self-sow but, by the same token, seem to lose strength after a few years so you will need to supplement your love-in-a-mist with additional seeds from time to time.

Tip of the week

Everyone knows about star jasmine (Trachelospermum jasminoides), which is not a true jasmine but smells as if it could be. While star jasmine flowers especially in spring and early summer, lemon-scented jasmine (Jasminum azoricum) takes over in summer and fall.

Both plants can be grown as vines while, left to its own devices, lemon-scented jasmine will grow into an unruly shrub reaching a height and girth of 10-15 feet. You could actually plant the two of them together, alternating along a chain-link fence or block wall for an olfactory delight that will last from spring through fall.

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