There’s No Napping In Weed Wars Wide-Ranging Fight Against Knapweed Rages On Blackwell Island

Stuck to shoelaces. Wedged into tire treads. Sucked into the radiator of your car.

Seeds of the spotted knapweed have a hundred ways of moving across the landscape. If the foreign invaders take root in poor soil such as that on Blackwell Island, the weed quickly crowds out the native plants.

“When you invite the public to a heavily infested site like this, you’re encouraging them to take it to other places,” said Frank Frutchey, Kootenai County’s weed guru.

Frutchey is out to zap knapweed on Blackwell, which is in the Spokane River. The anti-knapweed campaign is part of a bigger project to transform a former landfill site into a boat launch and natural area.

Frutchey’s approach holds lessons for anyone who wants to stop the invasion on farms, along roadsides, in backyards.

The first rule of engagement: Know the enemy.

“Knapweed doesn’t like wet feet, and it doesn’t like shade,” said Frutchey.

It does like poor soil. That’s why workers were spreading fertilizer Thursday.

“We’re trying to tip the nitrogen balance of the soil in favor of grasses and against the knapweed,” said Frutchey.

The stiff, thigh-high remains of last year’s knapweed had already been mowed. That way, fertilizer and grass seed can reach the soil.

The grass seed will actually be drilled into the ground, using a device that belongs to the U.S. Bureau of Land Management. The bureau owns the island.

But first, the county will spray an herbicide that takes aim at thistles such as knapweed.

The chemical, clopyralid, is sold as Transline and is newly approved by the Environmental Protection Agency, Frutchey said. It won’t be used near the water, and won’t hurt the pines or other native plants.

Property owners also can use products such as Curtail, which contains 2,4-D, Frutchey said. That compound shouldn’t come in touch with conifers, though. Some products, such as Weed-B-Gone, contain 2,4-D but probably not in strong enough doses to hurt knapweed, he said.

It’s a good idea to spray in the spring, when knapweed sprouts as pale green “rosettes” and has yet to show its purple flowers.

“The older the plant gets, the hardier it is,” Frutchey said.

Are chemicals necessary?

In many cases, yes, according to Frutchey, although tilling the soil works well, too.

“Then you can plant what you want, and fertilize to favor what you want to grow.”

Knapweed can be hand-pulled, though it’s important to get the long taproot out of the ground.

Keeping up with the fast-growing species can prove nearly impossible. If you try it, Frutchey said, “it’s a good idea to wear gloves. A lot of people have an allergic reaction to knapweed.”

That’s because the weed has a poison of its own. It injects that into the soil. It’s using its own herbicide to fend off competing plants.

Animals won’t eat knapweed, unless they have no other choice. Explained Frutchey: “It’s the most bitter thing you ever tasted in your life.”

Knapweed was brought to the United States from the Middle East. With no Iranian insects here to munch on it, it flourished. Frutchey is among those who have been trying to get imported predators to take hold. In fact, the first place he released knapweed seedhead flies was on Blackwell Island.

That was 10 years ago. The flies are still there. So, obviously, is the knapweed. So Frutchey is pinning his hopes on another insect.

“We’re trying to get stem borers established. That will allow bacteria and fungus to enter the plants.”

Frutchey is a former federal soil scientist who bought a ranch near Rose Lake 20 years ago. That led, ultimately, to his part-time job as the county’s natural resources superintendent.

“When knapweed started coming into my neighborhood, I decided someone should do something about it.”