Did you know that young sunflowers follow the sun? They face east at sunrise, track the sun across the sky, and face west at sunset. The next morning they’re all facing east again!
This trait is called heliotropism but only young sunflowers do it.
Adult sunflowers always face east. That’s why this field is not facing the sun in the late afternoon — the flowers are (probably) adults.
How do sunflowers do this?
Their secret is explained this Science Magazine video.
Read more in this NPR article from August 2016.
(photos from Wikimedia Commons; click on the captions to see the originals. video from Science Magazine on YouTube)