Tamarisk: A congressman proposes an act to eradicate a shrub that drinks up to 300 gallons of water daily | SummitDaily.com

Tamarisk: A congressman proposes an act to eradicate a shrub that drinks up to 300 gallons of water daily

SUMMIT COUNTY – U.S. Congressman Scott McInnis introduced a measure to provide Western Slope residents with relief from the drought while simultaneously eradicating one of Colorado’s thirstiest noxious weeds.

McInnis’s “Tamarisk Research and Control Act of 2003” would grant $1 million to Mesa State College in Grand Junction to fund research and provide technical assistance to combat the shrub, which has taken root in the Colorado River Basin.

Tamarisk, also known as salt cedar, can grow almost as tall as a cottonwood tree. The shrub lines the banks of the Colorado River from Glenwood Springs down. According to Summit County noxious weed director Paul Schreiner, riverways are typically home to the most ecologically diverse plant life, but from Glenwood Springs west, tamarisk makes up about 90 percent of what grows along the banks of the river.

A mature tamarisk, with a tap root up to 50 feet deep, can drink up to 300 gallons of water – between 2 million to 4.5 million acre feet – each day. An acre-foot of water is the amount of water it takes to cover an acre of land to the depth of one foot, or enough to provide a family of four with its water needs for a year.

That’s water the Western Slope sorely needs, McInnis said. And removing tamarisk could provide increased water flows to municipalities and farmers, who, along with other Coloradans, are in the grips of what experts believe will be a multi-year drought. Removing the noxious weed would also allow native plants to return to areas from which tamarisk has crowded them out.

The tamarisk shrub hails from Eurasia and has displaced native vegetation on nearly 2 million acres in the Western United States.


The upstream march

Tamarisk has spread as far east as Eagle County, and Schreiner is worried it will reach Summit County’s waterways. The closest tamarisk shrub is near State Bridge on the Colorado River.

“It’s been on my radar,” he said. “It (tamarisk) can easily be transported up here on boats. The first place it will be is Green Mountain Reservoir.”

Green Mountain Reservoir, at the north end of Summit County, and the Colorado River are popular among boaters. Reservoir users, who are more likely to use motorized boats, can bring the noxious weed in from other places. Kayakers and rafters who use the Colorado River could easily bring tamarisk into Summit County when they raft or kayak the Upper Colorado to State Bridge and return – possibly with tamarisk on their equipment.

That’s what weed experts believe happened in Blue Mesa Reservoir in Gunnison, where they found a tamarisk last year – 25 miles upstream from the nearest stand of the weed.

According to Schreiner, not only does tamarisk drink copious quantities of water, it absorbs salt from the ground and stores it in glands in its leaves. When the leaves fall from the deciduous plant, the salt is reabsorbed into the land – effectively sterilizing the ground. Most native Colorado plants are salt-intolerant and won’t grow under a tamarisk.

Additionally, if a tamarisk branch breaks off and falls anywhere where there is water nearby, it will grow anew. Even pulling them up is a challenge, Schreiner said, because each branch has its own root system that funnels into the trunk of the plant; if any roots are left behind, they, too, will regrow.

Schreiner said that while he’ll keep an eye out for tamarisk, he’s more concerned about new populations of leafy spurge and spotted knapweed he found growing around Dillon Reservoir. The leafy spurge is located near the Church camp land northwest of the high school; the two populations of spotted knapweed are in front of the Lake View condos in Dillon and near the Heaton Bay campground.

He also anticipates that with lower water levels in the reservoir this summer, the former lake bed will serve as an ideal home for a white sea of false chamomile.

And the weed-eating goats aren’t coming to Summit County this year, either, he said. The county, itself in the midst of a budget crisis, isn’t funding the herd of noxious-weed-munching ruminants. Schreiner anticipates mowing the wetlands where the goats grazed last summer and applying herbicide later in the fall. He also plans to patrol the newly exposed sides of the lake’s basin seeking out new weed growth.

“It’s going to be a lot of seek and destroy,” Schreiner said. “This year, all the weeds will be horrid.”

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