Devilish Hawkweed Urgency Grows Over Finding Way To Curb Noxious Weed

(From For the Record, June 25, 1999): Sponsor incorrect: This week’s programs regarding hawkweed control were organized by the Benewah Soil and Water Conservation District. The sponsor named in a Wednesday article was incorrect.

Chop off its top, and hundreds of underground buds will sprout. Its runners creep out in all directions. Its seeds don’t need to pollinate, so a single one can start an infestation.

Just how bad is meadow hawkweed, which crowds out native plants and livestock forage? So bad that researchers have nicknamed it after an invasive Star Trek species controlled by an evil collective mind.

“At the university,” says Linda Wilson, “we call it the Borg.”

Wilson just earned her doctoral degree in plant ecology by studying hawkweed. Land managers from Alberta to Argentina call her University of Idaho office seeking advice on how to eradicate it. On Monday and Tuesday she shared her expertise with landowners in Benewah County, an epicenter of hawkweed infestation.

Last year, Richard and Wendy Wilks sprayed herbicide on their land near Elmira. The hawkweed bounced back stronger than ever.

“You can spend thousands and thousands of dollars out there and it’s not doing you any good,” Richard Wilks said.

As he spoke, Wilks stood in a field near Santa where Wilson is experimenting with fertilizer as a means of control, because it boosts competing grasses. The yellow flags marking her study plots nearly disappeared in a sea of hawkweed flowers. Yellow blossoms lit the rolling landscape in every direction.

Wilks pointed out how the hawkweed plants grow tightly beside each other. “Nothing will grow up through it. Pretty soon cattle would starve out here.”

Some noxious imported weeds have been in this region for a century, Wilson said, but meadow hawkweed is a latecomer. It didn’t show up west of the Mississippi until 1965, when it was found in Spokane County.

Imported insects are successfully chomping on some other problem plants, such as spotted knapweed and yellow star thistle. Wilson is looking for a similar “biological control” for hawkweed. But there’s not enough money to pay European researchers to identify the necessary insects, Wilson said. Even finding the plants in their native range is tough, because European insects keep them so well controlled.

“In its native range, it’s not a problem. It’s not a weed,” Wilson said.

Meadow hawkweed is one of 11 hawkweed species that came from Europe and have no natural insect enemies in the Americas. Orange hawkweed is also a problem in the Inland Northwest.

Strict controls must be used to ensure that imported insects don’t destroy the region’s native hawkweed species, which aren’t a problem because native bugs limit their survival.

Wilson recommends a variety of attacks on hawkweed. First off, landowners must pounce when they see that first patch of hawkweed plant.

“Spray it now, now, now, now! Because next year it will be half an acre.”

Not every herbicide works. In one Benewah County study plot, a promising new chemical called Plateau was tried. It didn’t faze the hawkweed, but zapped all the grass around it. In an adjoining plot, the herbicide Tordon killed some hawkweed and left the grass intact.

Ben Marsh, a weed management consultant, recommends using low rates of herbicides, but using them twice.

“If you’re going to get in there and use expensive chemicals, commit yourself to a second application in a season,” he said. “We can’t expect to go in and kill it early.”

He urges landowners to take advantage of state dollars available for weed control. “Benewah County had $3,000 last year for cost-sharing, and didn’t spend it all,” he said. “Those are your tax dollars coming back to the county.”

The Natural Resource Conservation Service also has money available for weed control, said conservationist Mark Addy, who organized this week’s sessions. His federal agency also offers technical assistance.

Wilson hopes more help will be available in the future. While the 1999 Idaho Legislature wouldn’t approve a tire tax that would have helped combat weeds, she said there are signs the state will catch up with the more aggressive tactics of neighboring states. She’d like Idaho to establish a weed-fighting trust fund like Montana’s.

The Wilkses first spotted hawkweed on their land in the early 1990s. It’s a major frustration, but they haven’t given up hope.

“We’re going to wage war on ours again this year,” Richard Wilks said.

Cut in the Spokane edition.