Contact: Kelly Allred, (505) 646-1042, kallred@nmsu.edu
Editor: Natalie Johnson, (505) 646-5714, njohnson@nmsu.edu
"Whenever there is any kind of wind, it just starts rolling, and it can roll for a long, long ways," says Kelly Allred, a plant scientist with New Mexico State University's Agricultural Experiment Station. "It bounces and rolls, and it'll just roll until it runs into a fence or something like that."
Although tumbleweed is a generic term for several different types of plants that snap off at the base and roll, Allred says what most people call tumbleweed is actually Russian thistle.
He says Russian thistle isn't even a real thistle; true thistles belong to the sunflower family. "It's a member of the goosefoot family, which includes fourwing saltbush and lambsquarter," Allred says. "It's an annual weed that adapts to a variety of habitats."
Russian thistle is a "prolific seed producer," with as many as 200,000 seeds per plant. "So it has a real capacity to spread long distances, as it bounces and rolls," Allred says.
Russian thistle is native to the steppe and grassland areas of Russia. "It first came to the United States about 1873 and was found in South Dakota," he says. "It came over with Russian immigrants in some flax seed. They planted their flax and this Russian thistle came up."
After that, the weed spread quickly, and within 20 years it hit New Mexico. "Someone first found it in Santa Fe at the penitentiary and along the railroads," he says. "Samples were sent here to the agriculture college at Las Cruces to Professor E.O. Wooton, who was an Agricultural Experiment Station botanist, and he verified it was Russian thistle."
In 1895, Wooton issued a report about the weed's spread. He offered the following advice for controlling Russian thistle and other invading weeds:
"Kill it first, if possible, whatever it may be, and find out its name afterward... There is but one treatment to recommend for (it) -- utter extermination from New Mexico, and let me emphasize this statement: Now, if ever, is the time to exterminate it!"
Despite Wooton's warning, Russian thistle spread unabated, not only in New Mexico, but throughout the West.
"Wooton tried to promote measures to control it," Allred says. "They tried digging up ditch banks and chopping it out, but there's too much seed and you just simply can't get it all."
The advice to just pull up Russian thistle as soon as you see it still applies today, says Richard Lee, a weed scientist with NMSU's Cooperative Extension Service.
"Since it's an annual, you don't have to worry too much about it coming back once it has been pulled up or chopped off," Lee says. "Also, both pre-emergent and post-emergent herbicides have been registered for controlling Russian thistle."
But it will take a little practice to recognize the weed in its early stages, because it looks much more succulent than the older, spiny version. In fact, Russian thistle is an edible plant in the seedling stage, while it can be toxic to livestock when its mature.
Luckily, Russian thistle doesn't show up too often in backyards in the city, Lee says. "You're going to see it in your agricultural fields, your cotton and chile and to a limited extent in alfalfa fields," he says. "But as far as the urban setting, you're going to find it mainly in waste areas."
If a homeowner does have a lawn that is heavily infested with Russian thistle, Lee recommends using a pre-emergent herbicide. "With a pre-emergent, you'll want to put it down pretty quick around this time of year, before Russian thistle starts germinating."
While city dwellers are pretty much spared from Russian thistle in their yards, highway encounters with the rolling beasts are frequent.
"You really have to think twice about how you're going to react when one's coming at you down the road, because they can get up to four or even five feet high and six or seven feet in diameter," Allred says.
When dodging tumbleweed doesn't work, you're likely to find yourself rolling down the road with the weed stuck to your grill.
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