A couple of South Carolina was doing its routine walk in the woods when it observed a strange phenomenon. A plant was swinging vigorously while there was no wind blowing.
This strange phenomenon can be explained by a study published in the American Journal of Botany entitled “oscillation frequencies of tapered plant stems”. This study was conducted in 2001 by researchers Hanns-Christof Spatz and Olga Speck. The key to this mystery are the extremely light winds that are imperceptible to humans, but which are able to move some plants.