The official blog of Evergreen's Master of Environmental Studies degree

The Summer of Knotweed

By Ben Harbaugh, 2nd year student. This Knotweed work was carried out during the summer of 2016. Ben is now completing his Thesis using data from his work with Knotweed.

ben with the knotweedClear skies in August mean brutally hot days. So the slight morning chill only heightens my wariness of the day’s coming heat. I force down a final drink of water before buckling my chest-waders and pulling on the full 15 liter backpack sprayer. My two fellow restoration technicians follow suit and we stride out into the field. Soon we arrive at a steep path descending down to the floodplain of the Satsop River.

Today, like almost every weekday from July to September, we battle an invading plant that is plaguing river systems across Western Washington: ‘The Beast from the East’ – Knotweed.

Knotweed is not hard to find. Its bamboo-like canes lean over the road near my parents’ house in North Seattle; its small cream-colored flowers bloom from across the road next to Capital Lake; its broad green leaves form an impenetrable thicket next to a random parking lot in East Olympia. In an urban setting not much separates knotweed from other common invasive plants like blackberry or English ivy. It’s there, nobody really cares, and perhaps that’s understandable. But if you see knotweed on the bank of a salmon-baring river, that means big trouble.

Knotweed spreads along river systems like wildfire, dominating riverbanks once established. And indeed, my team and I quickly identify several patches where we’re surveying along the Satsop River. We proceed with raining ‘blue death’ upon the knotweed leaves.

Our ‘blue death’ herbicide mixture is surprisingly only 1% herbicide, which stands in stark contrast to most herbicide mixtures that require upwards of 20% herbicide. Such a diluted mixture effectively kills knotweed because we’re using knotweed’s capacity for hoarding nutrients against it. Instead of nutrients, we ensure that these knotweed plants hoard a plant-poison. Sun Tsu would be approve I think – turning an enemy’s strength into a weakness. I like this aspect of knotweed work.more knotweed

Eventually my team and I arrive upon a real knotweed infestation. It’s difficult to fully appreciate how terrible knotweed can be until you’ve witnessed a knotweed forest. Standing 15 feet tall in some places, this particular knotweed forest spans for at least a solid acre.

I see in my coworkers’ facial expressions a new respect for our enemy. I suggest that they venture inside the forest to fully acquaint themselves with the plant. Upon returning, they describe the area below its broad leaves as a ‘dead zone’. I chuckle and agree with this assessment. We’ll probably spend an entire week spraying this knotweed forest.

I love my job controlling knotweed. It’s hard work, ecologically beneficial, and involves visiting in some truly beautiful locations. Furthermore, I relish the challenge of knowing that my job performance carries tangible environmental consequences. If I don’t bring my best effort every day, a hidden knotweed plant will slip past our ‘blue death’ and continue to haunt whatever river system we’re working on.

But the knotweed season doesn’t last forever – only so long as it’s hoarding nutrients during the dog-days of summer. And so it follows that I’m thrilled to return to Evergreen in the fall for my second year of MES. There’s learning to be had, a thesis to be written, and classmates to talk to.

Until next time knotweed. You beast.



  1. Hello CHRISTYJ,

    Just amazing and interesting information you hared here. Hope you will shared many more articles in future.

  2. the knotweed season doesn’t last forever – only so long as it’s hoarding nutrients during the dog-days of summer.

  3. I’m looking for this information. Thank you very much

  4. Kalk artık gel yanıma yorma beni

  5. Wslik pvp serverlerin tanıtıldığı bölmü

  6. bir melekti sanki.

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