Rounding the bend of a narrow dirt road that wound through the rocky high bluffs of the Utah backcountry, we came upon a plant I hadn't seen for many years. Hugging a frail ribbon of a creek was a thicket of tamarisk in full bloom.
Large, airy, rosy-lavender blossoms floated among the lacy, light green foliage and softened the sun-baked soil of the rocky canyon. In the cool oasis, the sight provided visual relief from the surrounding landscape. We stopped for a rest in the shade and I snapped a few photos.
I hadn't given tamarisk much thought until I had abdominal surgery in May and commenced a prolonged recovery. Numerous restrictions, infections and post-surgery complications have kept me close to home and cooped up. Between naps I read books, brochures, booklets, newspaper clippings, old notes and, at long last, magazine articles I said I would read when time allowed. Well, time has more than allowed and I've almost read myself silly.
When the current issue of the Sierra magazine arrived, the cover featured a view of the Colorado River at the bottom of the Grand Canyon. An enticing title "A Grander Canyon -- Whitewater and Weed-whacking" tweaked my interest.
Flipping to the article, my mind was further perked by "When Aliens Attack" and the subtitle "How do you stop a troublesome species from taking root in remote corners of the Grand Canyon?" One plant at a time was the answer.
In addition to the fish-eye photo of the magnificent scenery, was an insert picture of a man sawing the trunk of a small sturdy tree. The cut line read "Mission impossible? A volunteer with a handsaw slays a tamarisk to make room for a native species."
Yikes! A tamarisk? It had never occurred to me that the graceful plant was an unwanted exotic. Could it be? I quickly scanned for the Latin name and sure enough, the tree being assaulted was "Tamarix ramosissima." Yikes! I remember selling tamarisk when I worked in a landscape nursery.
Indeed, the plant I once sold to grace a yard is now being hunted down and destroyed. Volunteer teams of concerned citizens are searching out this plant, which is also known as salt cedar, along the Colorado and its tributaries. By following the river, the "weed whackers" follow the invasion's path.
According to the article by Heather Millar, settlers imported tamarisk in the 19th century to create windbreaks and stabilize eroding riverbanks in the arid West. The species adapted well and spread to every river system in the Southwest, as well as other parts of North America.
Growing in thickets where plants were once sparse, tamarisk increases fire frequency and crowds out native cottonwood and willow. It also guzzles precious water in the species-rich riparian zones. Each year it's estimated that tamarisks in the United States suck up about three times more water than is used by all the households in Los Angeles.
As early as the 1920s the plants were established in the main Colorado River corridor of Grand Canyon National Park. In more recent decades the invader crept up the side canyons formed by the tributaries.
The effort to eradicate tamarisk is no small-scale operation. It involves a great deal of people power and money. The first phase of the endeavor involves removing it from 63 canyons formed by tributaries beginning within the park. A second phase will tackle 100 more areas; the third will move into eight larger tributaries, including the lower reaches of the Little Colorado.
Control methods vary: burn the trees, then come back to cut and poison the post-fire sprouts; inject slow-release herbicide pellets into the bark; spray chemicals from helicopters (oh no!); bulldoze the plants; and ax, saw or chainsaw the trees and apply herbicide. None work perfectly.
Tamarisk is one of the most aggressive alien species. It can survive total water inundation or extreme drought for prolonged periods. It hogs space, light and nutrients. It has no natural enemies in North America to help control its spread. A single shrub can produce over 250,000 seeds each year. Alien plant and animal species that are introduced, intentionally or inadvertently, often end up creating serious repercussions for native inhabitants.
On my very limited outings since reading the article, I spotted tamarisk blooming in full splendor in people's yards. I certainly looked at it differently than the day we stumbled across it in that cool oasis in Utah's backcountry.
Andrea LeE Lambrecht, naturalist and outdoors writer, can be reached at email@example.com.
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