Botanic Notables: The Tumbleweed

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Botanic Notables: The Tumbleweed

September 8, 2011
01:45pm
Photo by: Kris Light / Northern Arizona

Rambling over the desert steppe and into our romantic visions of the American West, the iconic tumbleweed is the Clint Eastwood of plants—an itinerant survivor that seems to thrive on solitude, parched land, and a mean wind. The gnarled forms blow through dry landscapes with a patient persistence, and a wind that whispers, "Keep moving, and you shall inherit the earth." And it just might, as the tumbleweed—which is, simply put, a mobile aggregation of seeds—rolls towards a horizon of disturbed habitats and unclaimed land, shedding seeds as it goes. 

Both the lonesome cowboy, and the traveling tumbleweed, started somewhere. Botanically speaking, a tumbleweed is a plant that whose roots release its above-ground body when its seeds are mature. At this point, the wind sweeps in, setting the tumbleweed—and its seed dispersal strategy—into motion.

The most common tumbleweed in the United States is called Russian thistle (Salsola pestifera), and, before the plant fell in with the wind, it was a rooted bush with flowers, stiff leaves, and up to 250,000 seeds. Designed to gambol lightly across its preferred habitat of arid, level landscapes, the tumbleweed breaks apart as it is jostled about. The pieces left behind are its seeds. 

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Russian thistle (Salsola pestifera) in Corona, California. Photo credit: Miheco, Flickr.

The tumbleweed has come to be an American icon, but the Russian thistle is not an American native. It was accidentally imported into South Dakota in the late 1870s by way of a flaxseed shipment from western Siberia. The wind introduced the new plant to its American terrain, which was not unlike the arid steppes of its native Ural Mountains, and the tumbleweed introduced itself to displeased farmers. The plant is a true desert and prairie plant and the Russian thistle absorbs an average of 44 gallons of water when competing with wheat. And its sharp leaves can pierce the skin—of a cowboy or his cattle, which makes for an effective survival strategy. A North Dakota legislator even proposed building a wire fence around the neighboring Southern state, to contain the invasion. However, tumblweed quickly spread across the country, eventually colonizing open spaces in 46 states. Wherever farmers had recently cleared land and tall prairie grasses, the opportunistic tumbleweeds would easily roll through town. 

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Tumbleweeds along Highway 211, Gila, New Mexico. Photo credit: Russ Kleinman.

Recently, however, the iconic loner has found redemption among desert scientists, who have been studying its effects in arid environments contaminated by nuclear weapons testing. In sites such as southern Nevada, where weapons have been tested, the tumbleweed is always the first to re-grow, and scientists have found that the plant actually removes depleted uranium from the soil, absorbing the toxic heavy metal into its own tissues.  

A Siberian immigrant and a "most-wanted" botanic scourge in the 1974 Federal Noxious Weed Act, the Russian thistle has nonetheless become a symbol of the American landscape, and a peculiar commodity. There are many online shops that will ship tumbleweeds "anywhere in the world," including a Kansas vendor who will tell you that "there's a new fad rolling into town," and suggests tumbleweeds as decor for your Western-themed wedding or store window display. They can be purchased in many sizes, at any time of year—for a tumbleweed Christmas tree, or snowman. And if a dusty brown doesn't fit your color scheme, they are available in designer shades—spray-painted gold, silver, or white.

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A tumbleweed snow man in California. Photo credit: JeffJohnston, Flickr

Anna Laurent is a writer and producer of educational botanical media. Photographs from her forthcoming field guide to Los Angeles are available for exhibition and purchase at the author's shop.