How Our Flora Know When to Blossom into Flowers

If we could see the miracle of a single flower clearly, our whole life would change.

By Stewart Edelstein

Against the backdrop of eternity, the Earth displays an ever-changing countenance. The harshness of blizzards yields to gentle showers. Inexorably, the cold, dark days of winter succumb to the warmth and light of spring. We welcome the renewal that is spring, a time when sprouts emerge from the softened earth, thrusting toward the sun to grow, over time, to their full ripeness.

And now — summer! The vernal equinox comes and goes. Our springtime sprouts mature to buds, each blossoming when the time is right, precisely as the energizing sun, nourishing rain and nutrient-rich soil enable our flora to work their magic by creating flowers.

How do our flora, including our flowering trees, know when a bud should be transformed into a flower? Plants, like humans, have an internal circadian clock by which they know when sunlight is increasing and our days are lengthening. This clock works because proteins, functioning as photoreceptors, are activated by sunlight.

These photoreceptor proteins ever so patiently wait … wait ... wait, until just the right moment, to signal that it is time to blossom. Triggered by that signal, each plant starts a molecular process that produces in its leaves a protein, known as Flowering Locus T. That protein travels to the tips of shoots, causing molecular changes in cells to begin forming flowers.

The summer solstice (June 21) is the time when the circadian clocks of our flora are signaling that sunlight will soon reach its maximum energizing effect, and that our days are some of the longest of the year. And so, especially in the height of summer, we take joy in the efflorescence of BBG’s more than 3,000 plant species in our many display gardens covering 24 acres.

If that scientific explanation is too much in the weeds (so to speak), just rejoice in the enchanting splendor of our rich pallet of flowers by ambling along BBG’s gardens, stopping as frequently as you wish. Linger as you really focus on flowers that appeal to you, and not