Like many invasive plants Japanese Knotweed (Reynoutria japonica or Polygonum cuspidatum or Fallopia japonica) was brought to this country intentionally from its native home in the volcanically active landscapes of Japan in the 1860’s as an ornamental and not surprisingly as a form of erosion control. I find it ironic that as industrialized “business as usual” continues unabated, even ‘volcanic’ in its destruction, we also find a rise in invasive species. As many of you know Knotweed is one of the most demonized plants of the Western/industrialized parts of the world, especially in urban areas. We thought there was nothing that could stop the rise of NYC real-estate but alas!…the presence of knotweed will compromise the value of your property and in the UK you can’t even get a mortgage. In our radicle efforts to SAY NO TO PESTICIDES and begin to understand the land we inhabit this article focuses on how we can successfully manage invasive species by utilizing their incredible benefits instead of allowing them to be labeled "biological pollution" and become part of an unsustainable waste stream. Like all good environmentalists know their is no “away”. Like it or not these plants are here to stay and it’s up to us to expand our minds and humble ourselves to the solutions that surround us.
I collaborated with Candace Thompson of The Collaborative Urban Resilience Banquet in hosting a workshop on the extraordinary ways we can have a relationship with Japanese Knotweed. This workshop was done with young teens from the Greater Ridgewood Youth Council as part of their environmental justice programing who have been attempting to eradicate Knotweed in Highland Park, Queens all summer with the environmental conservation group NYCH2O. Candace taught them how to make native bee-houses from the dried hollow shoots and I talked about how the roots are used as medicine and as a yellow/orange dye. Here are the results of our solutions and then some.
SAFE DISPOSAL: Please boil any part of the plant for 3-5min before composting. This will prevent further spread as any fraction of dried, frozen or fresh stem, seed or root part can establish just about anywhere.
Solution 1 - Dye
The yellow/orange Japanese Knotweed root bark can be harvested to make an incredibly beautiful light to deep yellow dye. The interesting thing is the fabric will change to a deeper orange/brown over time when exposed to light.
Solution 2 - Medicine
Knotweed root has been utilized as medicine for centuries to cure damp/heat and resolve toxins within the body. Known as Hu Zhang in Traditional Chinese medicine it is prescribed in formulation for treating fever, cough, hepatitis, jaundice, amenorrhea, vaginal discharge and joint pain. A seaseme infused oil has been used to treat sores, burns and venomous bites. 60-70% of the resveratrol supplement market comes from Japanese knotweed. Resveratrol is an antioxidant-like compound that supports healthy blood vessel function and overall heart health. It’s most popular medicinal use, as of late, has of course been in the treatment of the increasingly pervasive Lyme dis-ease. Some amazing resources for this medicine are Kamwo, Healing Spirits Farm and Avena Botanicals.
Solution 3 - Native Bee-houses
Our native North American Orchard Mason and Leafcutter bees are solitary cavity nesters and do not use communal hives like the non-native honeybee. We can help these native pollinators thrive, filling a symbiotic niche, by using the dried hollow shoots to houses are dear friends. The shoots are best harvested in the spring or fall as they begin to naturally dry out, are super easy to pull from the ground and once cut into desired sections are ready to use. For the bee motel roofs we used scavenged birch bark from the forest floor.
Solution 4 - Paper
Candace introduced us to an art collective from Ljubljana, Slovenia called Trajna who has been making “notweed” paper from the dried shoots. “NotWeed paper is the first paper brand that takes advantage of global environmental problem…” “Together with the local community we forage the thriving weeds in urban wastelands and use them as an alternative source of cellulose in the half-industrial paper production.”
Solution 5 - Food
Many foragers have begun harvesting the young spring shoots to eat in a variety of ways. I’ve seen laco-fermentation, cake, stir fry and pie. In her book Forage, Harvest, Feast: Wild -Inspired Cuisine Marie Viljoe offers eight recipes, for example, omelet, salad, jelly roll, meatballs and hummus that include knotweed as a main ingredient. Yum!