All romance aside, tumbleweeds are really just a type of invasive plant from Eurasia, known as "Russian thistle." After flowering and setting seed, this rounded bush displays a fascinating adaptation as it enters the afterlife. Ditching its roots and becoming mobile (with the help of the wind), it rolls all over the place and plays Johnny Appleseed, dispersing its numerous seeds as it goes.
Tumbleweeds easily become tangled up in fences and other obstacles, but a strong wind can shoot them along for miles. The best example of this we saw came while driving in northern New Mexico during a thunderstorm. High winds were whipping the rain in every direction -- but they were whipping more than just the rains. Tumbleweeds were crossing the highway with reckless abandon, bounding over every obstacle in their path like Olympic hurdlers. There's no way for me to estimate how great a distance those tumbleweeds traveled that night in just a matter of minutes!