Invasive monster tumbleweeds are coming to bury us

Tumbleweeds might look soft and fluffy from a distance, but hit one with your car and you quickly learn how woody, spiky and mean they really are. Just look at what happened when Victorville, California, got buried beneath tumbleweeds in 2018.

A new species of giant tumbleweed is now thriving in the US. Salsola ryanii is a hybrid that grows bigger than its parent plants. It can top 6 feet (2 meters) in height, so it's not like those cute little rolling tumbleweeds you see in Western movies. 

Researchers at University of California Riverside took a closer look at why this monster plant is thriving, and published a study in the journal AoB Plants. 

Salsola ryannii is created from a cross of two invasive tumbleweed species. It has extra sets of its parents' chromosomes, a state know as "polyploidy." Polylploidy is common in plants. For comparison, almost all humans have just one set of chromosomes from each parent.

The research suggests the tumbleweed's size and success is due to its polyploidy. As a hybrid, it's more vigorous than its parents. 

UC Riverside genetics professor and study co-author Norman Ellstrand described Salsoa ryanni as "nasty" in a statement last week. 

The plant, which has been found in California, may be looking to expand its territory. 

"It's one of the only things that's still green in late summer," study co-author Shana Welles said. "They may be well positioned to take advantage of summer rains if climate changes make those more prevalent." 

It may only be a matter of time before the Syfy channel makes a movie called Tumbleweednado.