To set the mood for shootouts at high noon in old cowboy movies, of course. Actually, tumbleweeds tumble to create future generations of tumbling tumbleweeds. The part of the tumbleweed you see blowing end over end in the breeze is actually the above ground portion of many species of desert plants. When the plant matures and dies, it breaks free from its roots in the ground and tumbles in the breeze, spreading new seeds along the way. When the seeds find suitable soil, they take root and sprout new tumbleweed.
Picture Credit : Google