An amateur gardener learns lessons from knotweed
You can learn a lot from Japanese knotweed — both from the plant, and from attempts to quell its spread.
Japanese knotweed goes by other names, including — but not limited to — monkey weed, donkey rhubarb and Hancock’s curse. If you’re a gardener, you may have already come up with names of your own. Fairly quickly, you learn to recognize the early red stalks peeking up, and then you know you’re doomed.
Well, not “doomed,” per se. Knotweed won’t kill you, but it will crowd out your peonies and roses. Ripping it up by the roots doesn’t do much but embolden the buried part of the plant to send out more shoots. If you see it on your property, it’s probably better to just move.
Well, not “move,” per se, but settle in for an eradication process that could take years, unless you have the wherewithal to have an earth mover come scoop away your entire patch — and then deposit that contaminated dirt down a very deep hole, or — better — shoot it into space.
But that’s really only moving the problem elsewhere. Sadly, according to Anne Rowlands, who with her husband, Will, runs Connecticut Gardener, that soil can then be sold to landscaping businesses, which may then move it — knotweed and all — into an unsuspecting customer’s yard. The smallest piece of the plant rhizome — the incredibly robust horizontal root system — can give you summers of headaches.
Road salt won’t kill it, and it grows fast. Rumors are that it can grow through concrete, but recent research from University of Leeds says it won’t. In Great Britain, the presence of Japanese knotweed on a property can affect a potential homebuyer’s ability to get a mortgage.
Still: We should all be so hardy. That’s lesson one, I suppose.
And here I should give my gardening credentials: I haven’t any. I am of the school of throw-it-in-theground-and-see-what-happens. I place placing seeds and plants in the exact wrong spot of the yard, and then I watch them die. I till acres of soil with dreams of fresh vegetables and herbs in the late summer, only to lose interest by early August and let the weeds take over.
But I am the dubious owner of a small patch of knotweed and over the last two growing seasons, I have learned so much at the foot of this damnable plant.
Lesson two: Gardening is a contemplative act. You can treat it as an attempt to bend your small patch of wilderness to your will, or you can accept that the wilderness will win, and you are simply a steward. When it comes to knotweed, you are something else again.
In a 2006 article in “Biological Invasions,” invasive plant expert Jacob N. Barney wrote that the plant was moved from East Asia to the United Kingdom as an ornamental jewel in the 1800s. The earliest recording of knotweed in the U.S. was in 1873, in New York City. The plant immediately jumped the fence and by the 1920s, its presence was called an “infestation.” So any thoughts of visiting a longdead landscaper’s grave to say bad words would be fruitless. Besides, revenge has no place in the garden (lesson three).
If you’re paying attention (lesson four), knotweed and other invasive plants bids you enter a new world. The Connecticut Invasive Plant Working Group formed in 1997 to keep track of the likes of knotweed. COVID put a halt to their in-person meetings, but their online symposium last October attracted 386 people. There are Facebook pages devoted to Connecticut’s knotweed, which can be found pretty much everywhere around the country. One page, Nix the Knotweed, recently asked for volunteers to come to the Pine Grove Spiritualist Camp in Niantic to address a patch. “If you can even hold a bag, you can help,” the Facebook plea said.
There was a fine turnout and the stalks were successfully snipped.
Around the state and throughout the summer, volunteers gather to enact what Rowlands calls the Rule of Three — snip the
stalks, bag them, and then return again during the growing season to snip and bag again. It can feel like an uphill battle. Add to the persistence of the plant, the birds and animals that eat invasive plant parts, and then scamper off to serve as roaming farmers with their dung.
Rowlands, a master gardener and a volunteer with the working group, says persistence overcomes the plant — lesson five. There is no quick fix, despite the fun of spraying something poisonous onto a weed and watching it die within minutes.
Knotweed is only one of the invasive plants that snake across Connecticut gardens and byways, Rowlands said. Add to the list
leafy spurge, ornamental jewelweed, and the misnamed tree of heaven. The invasive species take over the landscape and crowd out native plants. Matters aren’t helped much by unwitting gardeners (like me, I suppose) see a plant, decide it has a pretty smell/flower/look, and they leave it, in a form of Nature Deficit Disorder, not to be unkind.
Rowlands says once you become a gardener, it’s a natural step to then become an expert on invasive species. At this point, she removes invasive plants such as mugwort from her neighbor’s yard so the stalks don't move into her gardens. Her neighbors, who are renters, appreciate that very much.