How tumbleweed became an invasive species in the US
Tumbleweed is one of the most iconic symbols of the old American West, made famous in hundreds of movies.
But this invasive plant did not actually reach US shores until the latter part of the 19th Century.
Here's the story of where they came from, and how they came to dominate the mainland so quickly.
Produced by Sanjana Bhambhani and Tom Heyden
