Tumbleweeds aren't a type of plant. It's more of a description — the thing that happens when the bushy above-ground parts of lots of different types of plants dry, die, and disconnect from the healthy root system below. It is then free to blow wherever the wind takes it. That's your basic free-range tumbleweed. At Prairie Tumbleweed Farms, the weeds are a bit more constrained and they're shipped, rather than blown, to customers all around the world. This podcast by Rose Eveleth is a cute, quirky piece, but you MUST listen to the whole thing. Because the backstory of Prairie Tumbleweed Farms is what makes this truly worthy of BoingBoing.