Making Use of Invasive Species: Japanese Knotweed on the Oregon Coast

Its exciting to consider the possibilities for creative management when we're looking at invasive species that are edible, medicinal, or have other "crop"-like characteristics like fiber for papermaking or material for building compost or making biochar. Interestingly, many invasive species feature at least one of these traits, and with a bit of ingenuity, their populations, and the ecosystems where they thrive, could be managed towards more biodiverse characteristics while creating economic value for land stewardship. In my heart of hearts, its sad that we are all tied in various ways to making money, and that stewardship practices are more likely to happen if they are tied to an economic outcome, but we'll save that post for another time!

  For now, I think its fun to engage with invasive species as allies in regenerating ecosystems, and one of the ways we can do this is by harvesting them and making use of their prolific growth. Last weekend, I had the opportunity to hang out on the northern Oregon coast and eat a bunch of Japanese knotweed (recently renamed Reynoutria japonica), among many other delicious spring edibles both native and weedy. 

  Jared Gardner of Nehalem River Ranch kindly set up a series of events including a talk in Astoria, a presentation in Manzanita, and an edible and medicinal plant walk at his ranch in Nehalem. 

    Some of the many plants we tasted and discussed included oxeye daisy (Chrysanthemum leaucanthemum), sow thistle (Sonchus arvensis), yellow dock (Rumex crispus), broadleaved plantain (Plantago major), narrow leaved plantain (Plantago lanceolata), wild radish (Raphanus raphanistrum), Canada thistle (Cirsium arvense), dandelion (Taraxacum oficinale), false dandelion (Hypochaeris radicata), and bull thistle (Cirsium vulgare). It was a veritable salad bar out there and we munched heartily on the vitamin-rich greens. We also discussed using Himalayan blackberry (Rubus armeniacus) leaves for tea, and blackberry roots for cough syrup and dysentery. And of course, Japanese knotweed, which is a prized edible and medicinal plant. Its young shoots and leaves are edible raw or cooked. Traditionally its used as a tea in Japan known as itadori.  The roots are prized medicinals in the traditional Chinese and Japanese medical pharmacopeias, and are also used by Western herbalists. 

  Japanese knotweed root is also one of the critical components of the herbal treatment for Lyme disease. Herbalist Stephen Harrod Buhner writes that Japanese Knotweed (Polygonum cuspidatum) has a wide range of actions. It is a long list, but worth citing here: 

  "Japanese knotweed is antibacterial, antiviral,  antischistosomal, antispirochetal, antifungal, immunostimulant,  immunomodulant, anti-inflammatory, antioxidant, antiatherosclerotic,  antihyperlipidemic, antimutagenic, anticarcinogenic, antineoplastic,  vasodilator, inhibits platelet aggregation, inhibits eicosanoid  synthesis, antithrombotic, tyrosine kinase inhibitor, oncogene  inhibitor, antipyretic, cardioprotective, analgesic, antiulcer (slightly  reduces stomach acid and protects against stress ulcers), hemostatic,  and astringent.

  A broadly systemic plant, Japanese Knotweed Root modulates and  enhances immune function, is anti-inflammatory for both arthritic and  bacterial inflammations, protects the body against endotoxin damage, and  is a potently strong angiogenesis modulator, highly protective of the  endothelia of the body. Its constituents cross the blood-brain barrier  where they exert actions on the central nervous system: antimicrobial,  anti-inflammatory, as protectants against oxidative and microbial  damage. It is highly specific for bartonella infections and good, but of  less importance, in mycoplasma infections.

   Japanese Knotweed Root is a very strong inhibitor of cytokine  cascades initiated by bacteria. During Lyme infection, for instance,  there is a spirochete-stimulated release of a number of matrix  metalloptroteinases (MMPs) which occurs through a particular grouping of  pathways. While there are a number of herbs that can reduce  autoinflammatory conditions stimulated by MMP-1 and MMP-3 (for example  Curcumin), the only herb that specifically blocks MMP-1 and MMP-3  induction through three particular pathways is Japanese Knotweed Root.

   Japanese Knotweed Root enhances blood flow, especially to the eyes,  heart, skin, and joints. This makes it especially useful in Lyme and its  coinfections as it facilitates blood flow to the areas that are  difficult to reach to kill the organisms. The plant’s compounds easily  move across the gastrointestinal mucosa and circulate in the  bloodstream.

   Japanese Knotweed Root is an angiogenesis modulator, stimulating the  formation of new blood vessels and the healing of damaged ones in areas  such as burned skin, but also stops the development of new vessels and  blood flow in areas where it should not occur, such as in malignant and  benign tumor formation. It maintains the blood vessels themselves and as  part of this action, has specific modulating and protectant actions on  the endothelial cells that line the blood vessels."

   So in general the message is...go out and eat some knotweed! Its good for you (and please don't spray it with herbicide!)

   After the plant walk/salad bar, we did just that. Chef Andy Catalano prepared enjoyed a four course meal at the Salmonberry Saloon in Wheeler featuring Japanese knotweed prepared in at least 10 ways by my count. The event was co-hosted by the Tillamook Estuaries Partnership and the Lower Nehalem Watershed Council. It was heartening to representatives from these organizations present and engaged with the idea of managing invasive species differently.

Diners at the Salmonberry Saloon Knotweed Dinner Party

    First there was salad with tart young knotweed leaves and a dressing made with chevre infused with knotweed honey. Then there was risotto made with nettle/knotweed pesto. Next came knotweed braised beef shank with a pickled knotweed gremolata - like a roughly cut relish - on top. Dessert was a strawberry rhubarb coffee cake with knotweed strawberry gelato and knotweed puree. 

   A lot of knotweed was harvested to feed the 45 people present at the dinner. Did it make a difference in the population of knotweed that proliferates today in riparian areas along the north coast? Probably not. But there is definitely interest among the community there to think about different ways to see and interact with knotweed in particular and invasive species in general. 

  And the first place to start when thinking about knotweed is at the tops of the watersheds where it proliferates. The picture below is from the Nehalem River watershed:

  There's likely going to be some transformations in adjacent waterways from "forestry" practices like this - erosion and sediment deposition leading to channelization and bank scouring to name a few....none of these things leads to the proliferation of native riparian vegetation. Looking back a few decades at the same watershed gives some further clues regarding why riparian areas may be prone to different vegetation types:

  Throughout the Pacific Northwest, streams and rivers were used to store and convey logs cut from the uplands. Massive logjams such as these caused irreparable damage to streambank structure. So its no surprise that plants like Japanese knotweed are thriving today in places like these.

  One of the folks who attended the presentation mentioned that her name for knotweed is "knitweed" because in her observation its incredibly strong and prolific root systems appear to "knit" even bare stones together in the waterways. From there, brush and sediment pile up behind these small obstructions. Over time, they grow larger, and even larger debris and more sediment is held behind these "knitted'" areas. In this way, we could think of knotweed as working towards repairing riparian structure and function after a century and a half of wanton degradation.

Japanese knotweed root system - lots of soil in those roots!

     So, while eating Japanese knotweed and making use of its medicinal qualities by harvesting the roots can lead to some interesting and creative economic and ecological outcomes, these approaches to restoration need to occur in tandem with the larger picture necessity of addressing what's happening upstream. Without tackling those bigger picture processes and engaging with the hard conversations around transforming logging practices and the economy that surrounds conventional forestry in the Pacific Northwest, we won't be addressing the conditions that make knotweed and other similar species thrive. 

  Over the long term, I think we'll see the ecological role that knotweed is playing come into maturity - it will be so interesting to see what's growing amidst 'old growth' knotweed stands and bringing the riparian forest edge into the next stage of succession. Any guesses on what that may be?