Researchers Finally Decode the Science Behind the Dance of Sunflowers That Left Darwin Puzzled

In a study published in the journal Physical Review, researchers Orit Peleg from CU Boulder and Yasmine Meroz from Tel Aviv University revealed why sunflowers dance as they grow. Their study revealed that the random movement in sunflowers was a way to find sunlight.

Orit Peleg, a co-author of the study and an associate professor at the BioFrontiers Institute and Department of Computer Science, told ScienceDaily , "A lot of people didn’t really consider the motion of plants because, as humans, we were usually looking at plants at the wrong frame rate."

The mystery solved by these researchers even left Charles Darwin puzzled at one point in time. They found that sunflowers didn’t just grow straight up, but instead, they twisted and turned slowly. This phenomenon, called "circumnutation," helped the plants find sunlight and bloom, as noted by Knewz.com . Study leader Professor Yasmine Meroz explained while talking to The Killeen Daily Herald , "Previous studies showed that if sunflowers were densely planted in a field where they shaded each other, they grew in a zigzag pattern — one forward and one back — to avoid being in each other's shadow."

The directional movement of plants fascinated Darwin after his return from the HMS Beagle voyage. In the 1860s, as he dealt with health problems, he enjoyed observing plants grow. He planted cucumber seeds and watched how their tops twisted and turned each day, creating random and wild patterns. Chantal Nguyen, lead author and a postdoctoral researcher at BioFrontiers, said, "Our team did a lot of work on social interactions in insect swarms and other groups of animals. However, this research was particularly exciting because we were seeing similar dynamics in plants. They were rooted to the ground."

In 2017, a study conducted by the University of Buenos Aires showed how sunflowers naturally formed a zigzag pattern, like a zipper, to get more sunlight as a group. This made Meroz wonder, "For climbing plants, it’s obvious that they moved to search for supports to twine on. But for other plants, it wasn’t clear why this movement was important."

The wiggling of sunflowers also helped farmers find new ways to arrange crops for better growth. With this knowledge, farmers could develop better planting methods, leading to higher yields while using fewer resources like water and fertilizers. To explore the patterns further, researchers planted five one-week-old sunflowers in rows and mapped how they moved over a week.

They noticed the wiggling patterns and found that if the plants didn’t wiggle, they would bend away from each other in a straight line. However, if they wiggled too much, they would grow in random directions, disrupting the ideal crowded crop setup. To grow efficiently, sunflowers needed just the right amount of wiggling movement.

Meroz noted, "This was somewhat like a crowded dance party, where individuals danced around to get more space: if they moved too much, they would interfere with the other dancers; but if they moved too little, the crowding problem wouldn’t be solved, and it would be very crowded in one corner of the square and empty on the other side." She added, "Sunflowers showed a similar communication dynamic — a response to the shade of neighboring plants, combined with random movements that occurred regardless of external stimuli."