Why Sunflowers Face East

August 16, 2021

While sunflowers are growing, their stems bend back and forth to track the sunlight during the day.  However, this movement comes to a halt once the sunflowers bloom, leaving the heads to face East. Now, recent research from scientists in the Blackman Lab explains why sunflowers face East: morning warmth helps sunflowers attract more bees and also reproduce more efficiently.

The study, titled "Flower orientation influences floral temperature, pollinator visits and plant fitness,"  was co-authored by associate professor Benjamin Blackman, postdoctoral researcher Srinidhi V. Holalu, and former undergraduate researcher Daniel Yang, along with a group of researchers at the University of Virginia and the University of California, Davis. The study was published in the journal  New Phytologist  on August 9th, and it was supported by grants from National Science Foundation and the U.S. Department of Agriculture-National Institute of Food and Agriculture.

Learn more about the research and its implications in a recent UC Davis press release. View a video of sunflower movement directly below:

Bees visiting west-facing (left) versus east-facing sunflowers in the morning. Facing east allows sunflowers to warm faster and affects development of florets, promoting pollination and reproductive success. Video courtesy of UC Davis.