Japanese knotweed really gets your attention in late fall, here in East-Central Ontario. When the leaves of most other plants have almost all dropped to the ground, knotweed leaves hang on. Like beech or oak, knotweed’s brownish leaves will stay on past the first snowfall. But there’s something about their colour against a white background that grabs you. It’s a bit too orange, or even slightly pink. If leaves are something you spend a lot of time looking at, Japanese knotweed leaves will jump out at you.
If you get worked up about invasive or alien species, that colour could easily look a little sinister to you. But I think calls to eradicate the plant are misguided. And that’s not just because Japanese knotweed Root is becoming more and more important in North America as part of herbal treatments for Lyme disease. It’s also because getting rid of it is wildly impractical.
Don’t make an enemy…
I harvest Japanese knotweed root for medicine. I’ve unearthed roots as thick as my forearm that were coiled so wildly that they looked as if they were growing through each other. They’re tenacious and interlaced, digging down and across and through all types of soil. I’ve seen them breaking up concrete walls and churning through compacted gravel soils.
If you’ve spent any time digging up knotweed roots, you will have some respect for the strength of this plant. Unless you’re proposing an army of thousands and the heavy equipment to go with it, and maybe even then, you’re not going to eradicate Japanese knotweed. Sure, if it were growing within 20 yards of my house, I would take steps to control it. Because I’ve seen what this plant can do, I’d try to come to an understanding.
You can watch, even in a single season, how knotweed creates the conditions it needs to thrive. In well established patches, the crunchy, decomposing layer of hollow stems mixed with leaves can be 12 inches thick. That mulch layer is like a highway for knotweed roots. I’ve followed roots that looked to me as if they’d traveled laterally for six or eight feet in a single growing season. I’ve also discarded very small pieces of what looked like dead root material in my yard, and watched them valiantly put out new shoots in spring.
When you can make a friend.
The bark of the old, thick roots is an unassuming dirty brown. But just under that bark is an unmistakable signature of this plant; the inner bark is bright orange. It’s not quite the orange of a carrot, but it’s close. More like fresh turmeric.
As a medicine, Japanese knotweed has become vital to thousands of people with Lyme disease. I supply Japanese knotweed root powder as well as dried, chopped root to dozens of customers and practicioners. I even harvest some fresh root for tincture makers. My customers tell me how indispensable knotweed is to them. They’re either using it to treat acute Lyme, or maintaining their health after coming back from the disease.
I’m not a clinician. I just harvest roots. There are lots of people with a deeper and subtler understanding of this plant and of Lyme disease. Look up two of my favourites, Stephen Buhner and Steven Martyn.
Japanese knotweed root is part of the traditional East Asian pharmacopeia. It’s most commonly known as Hu Zhang and Itadori, and is used to “excrete dampness and remove jaundice, clear heat and remove toxicity, resolve blood stasis and stop pain, resolve phlegm and relieve cough.” https://tcmwiki.com/wiki/hu-zhang. From what I understand, it acts on the liver, gall bladder and lungs. It’s also been shown to have high concentrations of resveratrol (J. Agric. Food Chem. 2002, 50, 11, 3337-3340), the compound that has made red wine’s health effects so famous.
This plant is beautiful and graceful. It grows to seven feet high or more in Eastern Ontario where I harvest it. We have a short, near-north Canadian growing season, and it still manages to arch its hollow stems up that high and spread its big leaves out for shade, before dying back and regenerating from the root.
Itadori, I’ve been told, can translate literally as “remove pain.”.
How is Japanese Knotweed here to help?
Japanese knotweed blooms late, into October around here. The sprays of tiny white flowers are just about the only thing blooming at the time. So they’re usually covered in a symphony of bees. knotweed flowers are a vital late-season food source.
I’m neither a botanist nor an environmental scientist, but it sure looks to me like knotweed provides some other vital services to its environment. I’ve seen first hand how it loves disturbed soil. That’s another reason it’s hard to eliminate. Trying to get rid of it creates conditions that it loves.
It also loves slopes and banks of waterways. The wild, tangled network of roots clearly stabilizes those soils. What does this plant’s root system have to offer us in an era of unpredictable rainfall, and potentially greater flooding?
Harvesting Japanese knotweed means crunching through a thick mat of hollow dead stems. The hollow, bamboo-like stems from previous years dry and flatten out to make layer of mulch. I can only wonder at how much that mulch shades and retains moisture in the earth, and how fast it decomposes and make new soil. What plants – like the pink trillium on the left – will take advantage of that shady, moist habitat?
When I see how Japanese knotweed can break up and wrap itself around concrete, it makes me wonder what role it has to play in remediating land that’s been used too hard.
And you can eat the early shoots. Before the leaves unfurl they’re crunchy and sour, and might remind you of asparagus. But learn from my mistake: think of it as a fruit, not a vegetable. So don’t think asparagus. Think rhubarb. Make pie. Don’t make an omelette. Here are some recipes.
If you must do battle…
Like I said, if I had Japanese knotweed growing close to my house, I would try to convince it to go elsewhere. Without an excavator, I’d steel myself for several days of digging by hand. I’d also know that I was never going to get all of it. It can reproduce from small, seemingly dead pieces of root. And all the disturbed soil is really an invitation for it to spread out and do its life’s work. So I’d replace it as quickly as possible with a bushy, fast-spreading plant that had a chance to take over. I’ve seen Comfrey (Symphytum uplandica) compete with knotweed pretty well. But I would expect that I’d be seeing little shoots every spring, and going after the buried roots for years to come.
There’s another thing I would do: I would take a piece of root and plant it somewhere else. I’d plant it somewhere I wouldn’t mind it being. A plant-whisperer friend of mine, who is a career landscaper, told me about wild patches that she has watched for years. They barely moved or grew in the 10 years she worked on that property. It seems that knotweed can find a niche and be content.
A spiritual choice.
To some extent, deciding that Japanese knotweed might be a friend is about your outlook. I don’t believe that the natural world is essentially hostile to us. I don’t think it’s full of scary plants that we need to protect ourselves – or other plants – from. The world is operating on a time-scale and with a level of complexity that are both so much greater than we will ever get to understand. Whether we do it as scientists, sick-people or plant-whisperers, the best we get to do is to peer into that complexity and hope for some small insight.
I also don’t believe that the natural world is random. I think that nature is making intelligent choices. And wisdom is learning to imagine the benefit of those choices, rather than trying to control them.