Like cowboys, wagon trains and buffalo, tumbleweeds are icons of the Old West. These twisted balls of dead foliage rolling across deserts and the open range are staples of Western movies and the American imagination.

But the truth about tumbleweeds isn’t so simple. They may be romantic symbols of our national love affair with the Wild West, but tumbleweeds are also invasive weeds called Russian thistle, and many modern-day Westerners fear they’re taking over.

How they got here

In 1873, Russian immigrants arrived in South Dakota carrying flax seed that was apparently contaminated with Russian thistle seeds (Salsola tragus). Once sown, these invaders from another continent quickly sprouted, unhampered by natural predators and diseases to keep them in check. Each winter after Russian thistle plants die, the brittle bushy parts snap off at the roots and blow away, dispersing seeds wherever they tumble (about 250,000 per plant).

Because Russian thistle thrives on little precipitation and easily exploits disturbed land stripped of native species, it was able to quickly take hold in the vast agricultural fields and overgrazed rangelands of the arid West. By the end of the 1800s, this intruder had already rolled its way across most western states and into Canada, carried by wind and even railroad cars.

A government botanist sent to investigate in the early 1890s could barely believe his eyes: "One almost continuous area of about 35,000 square miles has become more or less covered with the Russian thistle in the comparatively brief period of twenty years."

Life of a tumbleweed

Tumbleweeds can grow several feet high. miheco [CC BY-SA 2.0]/Flickr

When we think of tumbleweeds we rarely picture fledgling Russian thistle bushes, which many consider beautiful with their reddish purple striped stems, tender leaves and delicate flowers. Growing from six inches to three feet tall (with some sprouting to Volkswagen Beetle size), they later develop sharp spines.

Many animal species feed on the succulent new shoots, including mule deer, pronghorn, prairie dogs and birds. Russian thistle hay actually saved cattle from starvation during the Dust Bowl of the 1930s when other feed wasn’t available.

Russian thistle is beautiful in bloom before it dries up and tumbles away. miheco [CC BY-SA 2.0]/Flickr

But there’s a down side. Tumbleweeds have never stopped spreading. Nearly every state in the U.S. is now home to Russian thistle, as well as several newer tumbleweed species that arrived as immigrants from around the world.

The ongoing drought out West has been a particular boon for these ubiquitous raiders, launching a recent explosion of prickly spheres rolling across mesas and through canyons and towns, and even creating a new giant hybrid species that’s currently sweeping across California.

Today, tumbleweeds are not only an agricultural nuisance and fire hazard, but as CNN reports, massive pileups now often bury houses, block roads and driveways, and even barricade people inside their homes, as seen in these videos:

On New Year's Eve, state troopers in Washington state spent 10 hours digging motorists out of a tumbleweeds that were piled 20 to 30 feet high on the roadway. They called the mess "tumblegeddon."

"Visibility was bad, which caused cars to slow down," Washington State Patrol Trooper Chris Thorson told USA Today. "When they stopped, the tumbleweeds were piling so fast, they just fully engulfed in minutes. It’s kind a strange mixture of weather and circumstances, I don’t know how to really explain it. It’s just odd. It’s so odd because it doesn’t happen. Typically, 99 percent of the time, you can drive through tumbleweeds."

American emblems

Tumbleweeds were already a detested farming pest and fire threat back in the late 19th century, but that didn’t stop them from becoming immortalized in 20th-century Western movies as rugged roamers, symbols of our national reverence for resilient individualism, wide open spaces and rambling frontier freedom.

Two Westerns were named for these shrubby lone drifters — a 1925 silent film called “Tumbleweeds” and a 1953 Audie Murphy flick named "Tumbleweed." A 1935 Gene Autry movie titled "Tumbling Tumbleweeds" also featured a hit song by the same name.

Listen to a later version from singing cowboy Roy Rogers and the Sons of the Pioneers in this video:

Tumbleweeds continue to inspire everything from book and film titles to restaurant, business and band names — a testament to their mythical force first etched into the American psyche through the power of the big (and little) screens.

Check out this movie and TV montage of iconic tumbleweed scenes by the Columbus Museum of Art:

Tumbleweed takedown

The war on Russian thistle and other tumbleweed species stretches back almost to the time of their accidental arrival. Tried-and-true management options include applying pesticides and mowing down young plants or yanking them out before seeds have a chance to develop. But these methods are often expensive and time consuming.

In response, scientists have begun testing several biological options, such as killer insects that can take out tumbleweeds naturally and more efficiently. In addition, the U.S. Agricultural Research Service recently announced the discovery of two promising fungal pathogens that infect and kill tumbleweeds. Not surprisingly, the fungi were uncovered in infected Russian thistle plants growing on the Eurasian steppes — the original home of tumbleweeds.