- The Washington Times - Sunday, August 29, 2004

KEENE VALLEY, N.Y. - Fat, red-speckled shoots of Japanese knotweed, like a forest of blood-spattered asparagus spears, emerge each April from a mound of dead canes to form a jungle of 10-foot-tall plants.

Their rhizomes spread underground 25 feet in all directions, sending up shoots tough enough to pop through pavement. If rhizomes reach a brook, bits break off and take root miles downstream. When rhizome-infested soil is hauled away by ditch-digging highway crews and later used to fill a washout, a new jungle will sprout there.

“This plant is the bane of my existence,” said Steve Flint, who heads an invasive plants control program for the Nature Conservancy. “It loves riparian corridors. It’s very resistant to herbicides. If you mow it, it spreads like wildfire because every chopped-up bit will grow into a new plant. It’s incredibly tough to eradicate it.”

From early June through mid-October, Mr. Flint virtually lives in the field, working to nip in the bud the alien species that threaten to overrun the Adirondack Park as they have other parts of the country.

If invasive species are left unchecked, native plant life that is part of the allure of the Adirondack wilderness could be lost. Multicolored meadows of orange hawkweed, bluebells and black-eyed susans could give way to monotonous white stretches of garlic mustard or wild chervil. Boreal bogs could be choked by purple loosestrife and giant reed grass.

That has happened in other prized natural areas, as well as in much of the nation’s urban and rural landscape. The invasion of alien species in the 6-million-acre Adirondack Park is still at an early enough stage that it’s possible to stem the tide with diligent management. That is the goal of the Adirondack Park Invasive Plant Program, a joint effort by the Nature Conservancy and several state agencies.

Topping the list of unwanted alien aquatic plants are Eurasian watermilfoil, water chestnut and curlyleaf pondweed. Targeted terrestrial invaders include purple loosestrife, Japanese knotweed, common reed grass and garlic mustard.

Japanese knotweed is typical of invasive alien species in that it aggressively crowds out indigenous flora and has no natural predators to keep it in check outside of its native Japan. The 10-foot-tall plants have bamboolike hollow stems, hand-sized, heart-shaped leaves and long clusters of tiny white flowers.

The plant, introduced to the United States a century ago as an ornamental, has been found in 36 states, with heaviest infestations in the East. It crowds the banks of the Allegheny and Ohio rivers and is considered a serious problem in Rock Creek Park in the District.

Knotweed has taken over streambanks in western Pennsylvania, displacing much of the native flora, said Kristin Sewak of the Kiski-Conemaugh River Basin Alliance, which was given about $250,000 from the state and federal governments to fight the invasion.

“It’s really difficult to get to the river in a lot of these areas where knotweed is prolific,” she said.

In northwestern Oregon, Jonathan Soll of the Nature Conservancy initiated a knotweed research and control program in 2000 along the Sandy and Clackamas rivers. Early results suggest that the most effective way to kill the plant is to inject herbicide directly into the stem, Mr. Soll said.

“Our research showed that manual control [digging or pulling up plants] is not feasible except in small areas like a back yard,” Mr. Soll said. “We found that it’s possible to control large knotweed patches using foliar spray of herbicide. Injecting it into the stem is even more effective and reduces the risk of harming native plants or waterways.”

In the Adirondacks, Mr. Flint attacks knotweed with pruning shears and a spray bottle of herbicide. On a recent morning, he knelt on a mound of old stalks resembling a beaver lodge, cut down plants and spritzed herbicide into each hollow stump.

Mr. Flint enlists armies of volunteers to pull up, cut and spray invaders. The control plan also includes teaching landowners and road crews to recognize alien species and stop their spread.

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