Nature in the City:  |
|
A mess of tumbleweeds fetched up against a fence in
Moscow after strong winds in November. |
by Sarah Walker, from the December 2006 Newsletter
During November, strong winds blew through town! Piles of carefully raked leaves escaped their tidy piles to spread back out all over the lawn, like no work had been done. Some big street trees succumbed to their weak spots and crashed onto sidewalks, cars and rooftops. And here came the tumbleweeds! Our smooth, flat streets and alleys are perfect openings for them to tumble through. Tumbleweeds crossed Main Street and even rolled up hills before ending their travels trapped in corners, piled against fences, and wedged under cars.
There are several plants with the word tumble in their common name. Most are not native to the U.S. The “official” tumbleweed is probably the annual in the Goosefoot family called Salsola kali, also known as Russian thistle and Wind witch. It matures into a big round shape that can reach the size of a Volkswagen, and is spiny and prickly. This is likely the plant The Sons of the Pioneers wrote about in 1932 with their cowboy song called “Tumbling Tumbleweeds.” The lonely cowboy in the song is travelin’ on, leavin’ his cares behind.
Deep in my heart is a song
Here on the range I belong
Drifting along with the tumbling tumbleweeds.
Free-wheeling, blown about by the winds, destination unknown.
Tumbleweeds are annuals, the plant life form whose mission, during its brief life, is to produce a lot of seed. Tumbleweeds produce thousands of seeds. They grow in disturbed and neglected areas like untended lots and along ditches, roadsides and railroad tracks. Despite efforts to kill them with formulas of heavy-duty residual herbicides, some tumbleweeds have developed resistance. They are thick along the railroad tracks near my house.
There are a couple of different species of tumbleweed here. We have the real McCoy, Salsola kali, which looks dark brown and very round. We also have its cousin from the same Goosefoot family, Kochia (KOSH-ah, Kochia scoparia), a branchy plant with wooly stems and inconspicuous flowers. It doesn’t have the rounded form of typical tumblers, it’s more conical, but that doesn’t stop it from traveling.
I think the tumbleweed that hopped my fence and landed on my deck during the blows of November is a Kochia from the railroad right-of-way half a mile from my house. In August, when I took walks there, I had noticed robust Kochia plants with bright magenta stems and diminutive gray-green leaves. The ones that orbited all the way to my yard made it across some very busy intersections.
The tumbleweed that makes really huge mounds against fences along our highways is likely Jim Hill mustard, Sisymbrium altissimum. In its dried up ready-to-tumble form the three-inch long seed pods are still visible. In very early spring Jim Hill mustard has bright yellow flowers and grows in swaths of three-foot tall plants along the highway, one of the earliest blooming plants here.
When tumbleweeds are ready to shed seeds, their stems break near the ground. In a strong wind—like 25 mph or more—they’re ready to roll and can travel long distances, depending on what’s in their way. This mode of dispersal makes them a very successful weed. They can spread seeds quickly over large areas. For instance, Salsola kali spread itself from what is believed to be its first North American location (South Dakota, in 1877) all the way to the Pacific coast by 1900.
NASA modeled an important robotic science tool after the free-wheeling tumbleweed. It’s called the Tumbleweed Rover. The prototype, a six-foot ball containing weather recording and communication instruments, was released at the South Pole and rolled 40 miles in 8 days, reporting back to headquarters in Pasadena along the way. No humans on board. No wheels, no motor.
This fall I thought I was doing pretty well to keep my leaves raked. Then came a few days of mighty winds and not only was my work undone, a new crowd of rotund and prickly tumbleweeds came calling, rudely demanding my attention. I couldn’t open my gate until I moved them aside!
|
Copyright: Copyright on articles, recipes and
images are jointly held by the Moscow Food Co-op and the respective contributors,
except were otherwise noted. |
For additions or corrections to this page, please contact the Webmaster.
