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Noxious weeds off to an early start

Stretch of warm spring weather has aided the early proliferation of noxious weeds, such as purple loosestrife and Japanese knotweed


An unseasonably warm spring has not only kicked many an Oregon vegetable garden into high gear, but it is also contributing to the early proliferation of noxious weeds in Columbia County.

Already, populations of purple loosestrife can be seen from Highway 30 between St. Helens and Rainier in the low-lying areas where water is present, said Crystalyn Bush, a field technician and outreach coordinator for the Columbia Soil and Water Conservation District.

And it’s not just purple loosestrife. Other water-loving species, such as

yellowflag iris, are also off to an early start.

“That’s a really diffi cult thing to control once it’s started because you have to be super careful with herbicides around water,” Bush said.

(Image is Clickable Link) SUBMITTED PHOTO - Japanese knotweed is listed by the World Conservation Union as one of the world’s worst invasive species. It’s found in Columbia County, and the Columbia Soil and Water Conservation District has launched an initiative to control and prevent its spread. Noxious weeds are invasive plants that overrun native species and cause significant harm to ecosystems where they take hold. A 2014 Oregon Department of Agriculture study, called “Economic Impact from Selected Noxious Weeds in Oregon,” found there is an estimated annual loss of almost $83.5 million personal income to the state’s economy from 25 selected weed species, with the bulk of the economic harm originating from Armenian blackberry and Scotch broom.

The economic harm is equivalent to the loss of roughly 1,900 jobs in the private sector, the study states, adding that, if left unchecked, there is a potential annual loss of $1.8 billion personal income and 40,800 jobs.

(Image is Clickable Link) SUBMITTED PHOTO - Herbicide applications help stop the spread of invasive species, such as
Himalayan blackberry. Prior to spraying herbicides, Columbia Soil and Water Conservation District staff recommends contacting the agency forguidance, especially for applications near water. “Noxious weeds cost millions and millions of dollars,” Bush explained. “They take over valuable land — forestry land and agricultural land — not to mention the effect they have on wildlife by reducing native plant species.”Some species, such as yellowfl ag iris, also contribute to stream bank degradation, she explained.

Arguably one of the worst invasive offenders in Columbia County, and one Columbia Soil and Water Conservation District is specifi cally targeting, is Japanese knotweed. In fact, the district has launched an educational outreach campaign following reception of a grant specifically targeted for Japanese knotweed control and is offering free herbicide spraying this summer for affected landowners.

“It’s big, it’s got red joints, looks like bamboo stems — really big heart-shaped leaves,” Bush said. “It’s widespread, so we reach out to tons of people.” Japanese knotweed prospers near water, but it can also invade a property’s drier, cleared areas.

Bush said one of the best ways for landowners to combat the spread and damage from noxious weeds is to be observant. “As a landowner, walk your property and know how to ID a few of the basic weeds,” she said. If one is spotted, she said, pull it immediately.

Also, she stressed the need to be careful about not transferring soil that could be contaminated with noxious weed plant pieces, as many can reproduce from stem and root fragments.

“That’s why they’re so successful,” she said. “They’re just really effi cient at reproducing and spreading.”

It’s also important to clean off boots and equipment after working in areas contaminated with noxious weeds, Bush said.

Bush said landowners should contact the Columbia Soil and Water Conservation District prior to applying herbicide to suspected noxious weeds or if there are any questions in general about noxious weeds and their control and prevention.

The district can be reached at 503-397-4555 or via its website at www.columbiaswcd.com.