I learned the term "heliotropic" when I was a college freshman,
Heliotropism is the diurnal motion of plant parts (flowers or leaves) in response to the direction of the sun.
Heliotropism was first described by Leonardo da Vinci in his botanical studies. The term "heliotropism," though, was introduced in the early 19th century by A. P. de Candolle, for the growth of the stem tip towards light, which is now called phototropism. The term heliotropism is now used only for solar tracking.
These day lilies eagerly stretching toward the sun are an excellent illustration of this concept. And tomorrow there will be a whole new troop, taking the place of today's bright band.
Love the color on this photo. Your day lilies are way ahead of ours, but after seeing these happy colors, I can't wait for mine to bloom! I always enjoy your little lessons too.
You captured the direction of those flowers perfectly. I believe I have some like that so they should be blooming soon since we're only a few weeks behind you in terms of garden growth.