Grays Harbor’s botanical battle

County weed control program at war with invasive and destructive knotweed

When Kiley Smith returned to the gravel bar below Twin Bridges on the Wynoochee River in 2018, she didn’t recognize it.

Smith, an Aberdeen native, visited the gravel bar often growing up. She knew it well. Her newfound sense of obscurity wasn’t due to her own forgetfulness or apathy, for her memories of the place were fond.

Rather, a persistent and prolific invader had muddled the river’s identity.

“I used to hang out on the beach down there when I was a kid, and it was just a sandy beach,” Smith said. “Then I moved back a few years ago, and I came down to it, and there was just nothing left of the beach. It was all invested with knotweed.”

Since her return to Grays Harbor, Smith, the Grays Harbor County Noxious Weed coordinator, has been locked in a battle — both a physical and strategic one — with knotweed, a broad-leafed and stiff-stemmed perennial shrub native to Northeastern Asia, in an effort to restore botanical balance and aid struggling salmon populations in her home watersheds.

“I care about all invasive weeds, but (knotweed) is jarring to see how impactful it is,” Smith said.

A drop in the bucket

A few miles south of U.S. Highway 12, near the confluence of the Satsop and Chehalis rivers, lies a peninsula of land cupped by a meander in the Satsop. The meander, for fishermen, is a likely spot to reel in a salmon.

The area is better known by county weed control crews as “knotweed alley.”

On Thursday afternoon, as Kelsey Sapp strode through knotweed alley, she — like Smith, although due to the opposite phenomenon — grappled with the sense of obscurity associated with returning to a familiar, yet altered, landscape.

In July, Sapp slung a 35-pound backpack filled with four gallons of Imazapyr, an herbicide used to treat knotweed, over her shoulder and trudged into knotweed alley, where she battled through a thick jungle of inch-wide stalks towering several feet over her head.

At the time, however, the stalks were bright green and encroaching on a four-wheeler path that provided the only relief from the weedy expanse. Crews broke several meters to the side of the path through the dense undergrowth to apply the herbicide.

Knotweed covered 85% of the forest undergrowth there.

Now, upon Sapp’s return, the stalks lining the path have begun to shrivel and brown, and the wide knotweed leaves have, for the most part, receded from the path, although the dying stalks, the walls of knotweed alley, still provide a thick, fibrous barricade to the rest of the forest.

“This is getting me excited for next knotweed season,” Sapp said.

Sapp, along with Smith, the rest of the county crew, the Washington Conservation Corps, contractors Brittland Inc., and others, treated roughly eight acres of Bohemian Knotweed at this site.

But despite the aesthetic change to the landscape Sapp witnessed and the grunt work it took to knock the weed down, this area’s knotweed growth is dwarfed by the expanse of untreated knotweed still living — and reproducing — in Grays Harbor County, most of it in the less-accessible areas than the lower Satsop.

“It’s such a drop in the bucket compared to the rest of the rivers,” Smith said. “People just don’t see it because it grows in places where people don’t go.”

Aquatic hitchhiker

This summer, the county’s noxious weed program treated 143 acres of knotweed across Grays Harbor, many of those acres in the Wynoochee and Satsop watersheds. But that extent of treatment is relatively novel for the county.

Prior to Smith’s takeover of the county’s weed program, the program’s role was mainly as a noxious weed educator, advising landowners and the general public to take steps for preventing the spread of noxious weeds, but wasn’t focused on physically eradicating invaders.

The altered landscape Smith saw near Twin Bridges four years ago was widespread in Grays Harbor watersheds. According to a 2018 map from the department of agriculture, Grays Harbor was the only county in Washington infested with over 1,000 acres of Japanese Knotweed.

That changed when Smith started applying for U.S. Forest Service and Washington Department of Agriculture grants, which allowed Smith to hire crews for weed control projects, in addition to continuing education and outreach. But some of the county’s early knotweed control efforts didn’t go as planned.

Knotweed, Smith explained, is an aquatic hitchhiker. It grows in riparian zones — the interfaces between land and rivers.

Smith said even though knotweed’s roots are deep and wide, they don’t hold banks intact as well as native vegetation, like willows and grasses. When water levels rise and seize the soils of undercut banks, knotweed’s brittle roots give way and catch a ride downstream.

“We have huge erosion issues already occurring on our rivers,” Smith said. “The knotweed destabilizes things, so it causes worse erosion, so it’s making the rivers go crazy, threatening houses and taking acres off of people’s pastures.”

Later, when flood waters spill into riparian zones, they deposit those roots elsewhere, allowing the invader to spread.

“Anywhere that the water touches has knotweed in it,” Smith said, adding it takes roots only one inch in length to grow a new knotweed plant.

Treating only the lower reaches of a river, Smith realized, wouldn’t fully control the plant.

“I have seen areas where I treat the lower reaches, I came back the next year expecting good results, and it was all brand new growth of this plant,” Smith said.

Smith changed her strategy, venturing with crews into the far upper reaches of the Wynoochee, “hiking up and down rivers in pretty crazy terrain” each summer.

“Bless the hearts of my crews and contractors,” Smith said.

Today the program has sprayed 17 river miles and worked with over 100 landowners on the river.

The state of Washington classifies noxious weeds into three categories — based on both how threatening a weed is and how prevalent it is — which outline weed control policy for individual counties. In many cases, weeds that are already widespread don’t garner strict control because full eradication is virtually impossible.

Knotweed is a Class B weed, meaning that in places where it’s already abundant, like Grays Harbor, county weed boards designate weeds for mandatory control.

Smith said property owners in Grays Harbor County can choose whether or not they want to work with the county to control knotweed. If landowners were to attempt to control the weed themselves, it would require a special and unlikely permit. Smith said since many infestations occur on private land, the effectiveness of watershed-wide knotweed control depends largely on the willingness of landowners to work with the county’s weed program.

Many landowners are on board, Smith said, because of the threat to property the weed poses. And government funding is usually available for knotweed control, and likely will be in the future, because of those property threats and detriments to salmon, Smith said.

Knotweed control, Sapp and Smith agreed, can feel like a losing battle. But Smith’s motivation to keep fighting the noxious weed battle, is a personal one, as well as a professional one.

It’s a quest to return her home rivers to the state of her youth.

“The rivers just aren’t the same as when I was a kid,” she said.