I dream of knotweed: the Water and Land Resources Division at work

Crossposted from the King County Downstream blog, originally posted on September 25, 2020.

By Gavin Tiemeyer.

What does it take to be a Noxious Weed Control Specialist with King County? Prior to the pandemic and public health social distancing measures, author Gavin Tiemeyer spent the day on the Cedar River with Sayward Glise and Matthew Martin in order to find out. The short answer: knowledge, a sharp eye, a good attitude, and a trusty pair of blue work overalls.2019-nw-martin

Matthew Martin and Sayward Glise follow an area along the Cedar River known as Byer’s Curve, in search of hiding knotweed plants.

It was 9 a.m. on a sunny morning near an area along the Cedar River known as Byer’s Curve in unincorporated King County. At first glance, what appears to be a nondescript green-space, nestled between two residential properties, is actually a bustling riparian ecosystem with plants and animals competing for sunlight and water.

This is where the noxious weed control specialists will search for — and try to eliminate — knotweed and garlic mustard, two tenacious invasive species of plant that, left unchecked, can wreak havoc on the river’s ecosystem.

“Knotweed is one of the most aggressive invasive species in North America, and it loves our rivers,” Sayward explained. “Once it gets established it quickly out-competes the native vegetation. Our mission is to control knotweed, improve water quality, and restore riverine habitat.”2019-nw-sayward

Sayward Glise, Noxious Weed Control Specialist, inspects the looming stem of a flowering knotweed plant (2019).

Managing knotweed is a major undertaking for King County and is especially important along the Cedar River where control is regulated. Sayward explained that knotweed clones itself in big flood events on the river when the plant’s root base breaks apart easily and travels downstream to other locations.

The way the process works is this: working closely together, Sayward and Matthew move through the greenspace by “gridding” or “running transects” in order to track down knotweed.

“We move strategically through the space in an effort to get visual coverage of the entire site,” Sayward explained. “We use maps, our GPS track logs, landmarks, and lots of verbal communication to make sure that we are getting our eyes on the whole site, and hopefully finding every stem of knotweed.”2019-nw-knotweed

Matthew and Sayward plan out transects in order to find hidden knotweed (2019).

My job was to follow Sayward and Matthew around closely with a large black trash bag for proper disposal of litter and garlic mustard sprouts — another noxious weed that the county is required to control. I was amazed at how effortlessly they find the plants they are looking for. Matthew compared the process to the way birds of prey use shapes to hunt.

“Pretty much in here, I’m looking for leaf markings that aren’t jagged. Anything smooth,” Matthew said without breaking his stride. Taking his advice, I looked for smooth-edged leaves, but all I saw was a field of green plants. I was unable to distinguish between good and bad. It was like looking for a green needle in a green haystack.2019-nw-martin-garlic-mustard

Matthew displays a pulled-up garlic mustard weed, known for its rapid spread by seed into natural areas.

Our search for weeds brings us within a couple of feet of a neighbor’s property. A family looked over at us briefly as they stained their back porch but seemed undisturbed by our presence.

“Do they know what we’re doing here” I asked Sayward, a little nervous about creeping in the woods so close to their house.

“Oh yeah. I called them earlier this week to let them know we were coming,” she said.

A crucial component of the work King County’s Noxious Weed control team involves establishing and maintaining good, communicative relationships with property owners. This makes sense, considering plants don’t decide where they’ll grow based on property rights. Some property owners can be leery of the presence of county employees though, requiring a good ambassador to communicate the mission of the Noxious Weed Control Program, while listening to the concerns and curiosities of the public.

Sayward Glise is just that person. Friendly and knowledgeable, with plenty of mom power, Sayward embodies King County’s good neighbor policy. Her kindness and passion for the work are apparent both in her enthusiasm to teach me and the way she interacts with neighboring property owners over the course of the day. She is a face they can trust.

On the origin of her career with King County, Sayward explained that she started with EarthCorps, and was able to network with King County project managers while doing work on the Cedar River. After some seasonal positions in the Noxious Weed Control Program, Sayward went after, and got, a full-time gig.2019-nw-sayward.2.jpg

Knotweed plants don’t stand a chance when Sayward comes to town (2019).

Despite the hard work, Matthew and Sayward praised the job they have. Though, occasionally a blackberry plant can stab you in the face.

“You go from a scream of frustration to busting out in laughter, because this is such a weird and unique job,” said Sayward.

For Sayward, after a busy day of treating knotweed, it’s common to go home and see the plant’s lime green leaves when she closes her eyes.

“I dream of knotweed,” she said.2019-nw-cedar

For Matthew and Sayward it’s especially important to find invasive plant species taking up valuable space along the riparian habitat of the Cedar River (2019).

By midday our search led us to an area along the Cedar River dominated by dense thickets of butterfly bush, another invasive species that can quickly out-compete native plants. Honeybees seem to love it, but Sayward explained that the larvae of native butterflies don’t like to eat the leaves. Apparently, invasive weeds escaped from victory gardens generations ago giving the plants a mythical quality.

Matthew spotted a large patch of flowering knotweed across the river and without hesitation waded into the knee-deep water to treat the plant on the other side. On days that are particularly hot, he explained, jumping into the river provides a welcome respite from the heat.

I first met Matthew while he was representing the Noxious Weed Control Program at the Duwamish River Festival. A recent graduate from the Environmental Science Program at the University of Washington, he is well equipped for the job. Using expert eyes, or what you may think of as a hawk-like vision, he spots plants one-by-one. Following him around with my black trash bag, he quickly outpaced me. I was sweating and regretting leaving my water bottle in the work truck.

The work Matthew and Sayward perform requires an attention to detail and knowledge of the land you can’t learn in a day. Using software on her phone, Sayward showed me a bird’s eye view of the zig-zag transects we’d made over Buyer’s Curve. Still more knotweed to find. Sometimes the invasive weed is a tiny seedling, other times it’s full-grown and hiding in plain sight.

To find every last noxious weed in Byer’s Curve we methodically move through the green space. Up and over nursery logs and through chest-high snowberry bushes, or “bee motels,” and “snowberry spider parties,” as Sayward calls them.

“It’s kind of new age, but I have this intuition, like a little voice that whispers, ‘over here,’” Sayward said. (I look in the snowberry to make sure nobody is secretly following us.)2019-nw-ivy

Sayward points to English Ivy, another tenacious invasive plant species, climbing up Cottonwood trees.

Between the three of us and the handful of plants we aim to eliminate, there were thousands of other living things going about their earthly business. The sights, sounds, and smells were evidence of this. It was easy to take for granted the soothing sound of moving water around us. The air had an intoxicating smell of ripe blackberries with a hint of cottonwood from the trees lining the river. Every sensory detail was heightened by the inhalation and exhalation of the woods. In the tranquility of our little green patch, it was hard to imagine the change that was happening from the impact of invasive species and climate change.

Sayward pointed out a garry oak seedling in the grass below us.

“I’m always excited to see these little guys growing out here.”

Garry oaks are a reminder of a time past when the Pacific Northwest was stewarded by the first people with the help of fire. “I think in no time this place will be a healthy riparian ecosystem again,” she said.2019-nw-trees.jpg

A day at the “office.”

The big payload at the end of the day was a large patch of mature knotweed on a property adjacent to the green space we had been working through. Sayward explained the property had recently been acquired as open space, to be managed by the county, through a voluntary sale by the owner and she had been waiting patiently to “take care of business.”

The property was large with a derelict greenhouse and a family home situated on the bank of the river. It was odd to look at a house so recently occupied by people that was now scheduled for demolition.

“Or you can think of it as prime habitat being reintroduced to the floodplain,” said Matthew.

When the work was done, we brushed off our boots to make sure we weren’t transferring unwanted plant seeds with us — a critical step that all field staff must do.

On the ride home I was exhausted and fighting to stay awake. I briefly dozed off in the backseat of the work truck. When I woke up, we are on I-90 just outside of Seattle. Then I saw it. Lime green, heart-shaped leaves, with little bunches of milky-white flowers. Knotweed hiding in plain sight. From now on, I will see it everywhere.


Gavin Tiemeyer is a graduate of The Evergreen State College where he studied environmental communication. He was a communications intern with the King County Department of Natural Resources and Parks in 2019 where he spent time in the field with employees of the Water and Land Resources Division to detail some of the work they do along rivers and streams to ensure clean water and healthy habitat in King County.

More reading on invasive knotweed and garlic mustard:

Invasive Knotweed – October 2016 Weed of the Month

Weeds don’t practice social distancing

Invasive knotweed identification and control

Garlic mustard identification and control



Categories: Program News

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