A decade ago, a member of the mustard family, alyssum, was planted around the Illinois Valley to see if enough nickel could be extracted from the soil to sell commercially.

GRANTS PASS — A decade ago, a member of the mustard family, alyssum, was planted around the Illinois Valley to see if enough nickel could be extracted from the soil to sell commercially.

The plant is a hyper-accumulator, meaning it takes up metals from the soil and stores them in its leaves.

The commercial venture and a five-year research project are both over, because "the soils were not as high in nickel as expected," said Mark Wiest, who ran the operation for Viridian Resources of Texas.

But the alyssum is still with us. In fact, it is now an invasive weed problem that could crowd out the rare flowers of Rough and Ready Creek and Illinois River drainages for years. About 160 acres were planted, most of it around the Illinois Valley Airport south of Cave Junction.

"A lot of people come here to look at our rare plants," said Suzanne Vautier of Kerby, a member of the Cultural and Ecological Enhancement Network who has pulled many weeds by hand. "We've got plants here that are found nowhere else in the world.

"This is going to be a long-term project."

The plant is native to areas around the Mediterranean Sea, and is perfectly suited for heavy metal-rich serpentine soils of the Illinois Valley. But here, with no native insects or diseases to threaten it, it's a ticking time bomb, said Ken French of the Oregon Department of Agriculture.

"It could become extremely dominating, especially with the way that Biscuit Fire burned around the Kalmiopsis Wilderness," French said. "That raises the concern level for alyssum to probably higher than any of the other threats the valley has, including Scotch broom, star thistle and knapweed. We're doing everything we can to limit the spread of this plant."

A full-blown eradication program began last year, with the help of an initial investment of $25,000 by Viridian, Wiest said.

French said the herbicide Escort has been used around the airport, where there were simply too many plants to pull by hand. Native flowers have already returned.

But in scattered colonies from Kerby south to O'Brien, people are hand-pulling the plants. French said he'll have a crew member dedicated to it this summer. Hand pulling is far more effective when the bright yellow plants are in bloom, starting about now.

The total acreage of the plants is 100 now after the initial eradication, but scattered over a large area, including near botanical areas on Eight Dollar Mountain, French said.

The plants spread because they "were either harvested too late or not harvested at all, and they produced millions of seeds," French said. "Viridian was supposed to manage this better than they did, by not letting seed mature and disperse."

Wiest said the flood of December 2005 put things "out of our control." French has found several plants along the West Fork Illinois River, likely from seeds swept downstream.

Nevertheless, Wiest is convinced the aggressive eradication last year has already put a huge dent in the population.

Robin Taylor-Davenport, Bureau of Land Management botanist in Grants Pass, said her agency and the Forest Service have had people out pulling the alyssum. She testified in 2009 when the plant was listed as a A class (highest) noxious weed.

Richard Roseberg, agronomist for the U.S. Department of Agriculture and part of the research project from 1998 to 2003, said ash from plants harvested contained 30 to 35 percent nickel. Typical nickel ore that is mined contains only 1 to 5 percent.

But the Illinois Valley wasn't a good fit because there wasn't enough flat, arable land to grow alyssum, Roseberg said.

"It's one of those things that was a great idea but for several reasons doesn't appear to be a good fit for commercial activities in the Illinois Valley," he said.