July 20, 2026
June 26, 2026
Ajisai (hydrangea) flowers: Kencho-ji
With its overflowing diversity of colors, the Ajisai garden captivates our hearts even under the gloomy skies of the rainy season. Mysteriously, Ajisai flowers lack the sweet scent of nectar that usually attracts pollinators. If they had a rich scent like that of roses, how enchanting would they be, together with the brilliant, ever-changing colors brought about by the chemistry of the rain water.
Flowers are reproductive organs designed for pollination. They are not meant to bring aesthetic pleasure to humans, but rather are equipped with various mechanisms to attract small pollinating insects.
Wild Ajisai plants grow originally in deep forests and along somber valleys, where the faint scent of nectar cannot spread widely and cannot be sensed by pollinators. If they had only small and inconspicuous flowers, they would not be easily discovered by pollinating insects.
Much of what we think of as petals—the blue, purple, and pink parts—are actually what are called "decorative flowers." Such decorative flowers are not petals at all, but are highly-developed conspicuous sepals that produce no seeds.
On the other hand, the small, inconspicuous flower in the center is a "hermaphroditic flower (true flower)" and this is the true organ where pollination takes place.
Ajisai spread large, eye-catching fake flowers to appear as a “cluster of flowers” in showy colors even from a distance and to guide insects to the small, true flowers in the center.
It is this magic trick for pollination that brings forth the colorful Ajisai flowers and presents us the joy of admiring them under the overcast sky in the rainy season.
Ajisai (hydrangea) flowers: Kencho-ji
Insect-pollinated flowers rely on insects to facilitate pollination for reproduction. The beautiful appearance of these flowers exists not for the joy of humans, but is arranged to suit the visual world of pollinating insects.
To ensure the survival of their offspring, such insect-pollinated flowers have evolved to display the colors and shapes that are easily detectable by pollinating insects.
They have adapted their forms to match insect vision and altered their shapes, colors, and ultraviolet reflection patterns (nectar marks) to display the seductive colors and shapes that are most easily found by insects.
Insect-pollinated flowers possess vividly colored petals and enchanting shapes to appeal to insect vision. Furthermore, they emit strong sweet scents to signal their presence to insects from a distance, secrete nectar as a reward to attract them, and provide nutrient-rich pollen.
Unlike wind-pollinated flowers, which rely on the fickle winds to disperse pollen, insect-pollinated flowers utilize the lively assistance of insects. This eliminates the waste involved in aimlessly scattering large amounts of pollen over long distances.
The color vision of insects has acted as the selective pressure that causes the evolution of flowers. Flowers have adopted the attractive colors and shapes for insects by elaborately altering their pigments and ultraviolet reflection patterns.
The colors, shapes, and scents of flowers, which we admire in every season, are the result of steady adaptations that enables trees and plants to survive in the lifelong struggle for existence and to sustain their prosperity of descendants.
Ajisai (hydrangea) flowers: Kencho-ji
Insects’ color vision is completely different from that of humans. It is said that they perceive the world primarily in ultraviolet (UV), blue, and green.
For example, honeybees’ color vision responds to these three colors—UV, blue, and green. Butterflies perceive colors ranging from UV to red. Flies have only poor color vision, but respond to UV. Moths can distinguish between white and pale yellow at night, and beetles respond to scent rather than color.
For humans, the color most commonly associated with flowers is red. However, it is said that to many insects, the color red appears almost entirely black. The colors that insects see most clearly are yellow, blue, purple, and white, and flowers are also equipped with ultraviolet patterns (nectar marks) that humans cannot perceive.
Flowers with these colors attract more insects, achieve greater pollination success, and, as a result, are more likely to produce offspring. The colorful appearances of flowers, which evoke a sense of fascinating beauty in humans, are essentially calculated survival strategies as living organisms and the result of wisdom refined over a long period of time.
Human-induced modification in the colors and shapes of flowers in selective breeding is based on this genetic adaptability of trees and plants, that has enabled them to survive in their harsh environment so long.
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