Column: A New Strategy for Invasives War
Absent a sustained effort, most attempts to eradicate invasives in a particular area do more harm than good. Here, a Vermont Youth Conservation Corps worker digs up Japanese knotweed along the Ottauquechee River in Quechee last August. (Valley News - Jennifer Hauck) Purchase photo reprints »
White River Junction
We have a weed that grows on our farm, Agropyron repens, commonly called quack grass or witch grass, that grows and sets seed like most weeds but also propagates via a network of rhizomes — white, underground rootlets that, if broken off during weeding, sprout to form new plants on their own. Quack grass is so effective at taking over fresh soils that highway crews deliberately plant it along roadsides to stabilize the soil after construction.
On the farm, we’re trying get rid of the stuff, not celebrate it, and we’ve adopted what I call the “85 percent rule”: leave the grass alone unless you have the time and ability to weed out at least 85 percent of it. And then make sure you have the time to come back within a month to get 85 percent of what’s left.
The worst way to deal with quack grass might be called the 50 percent approach: weed out half of it every now and again. This will cause the carpet of grass to grow ever thicker as you break up the rhizomes and redistribute them around the bed. Not only that, but you will have wasted valuable time that could have been spent more productively elsewhere, attacking a less pernicious weed or seeding a new crop.
I mention all this because now is the time of year when volunteers across the Upper Valley are fanning out into fields and woods to go after the invasive, exotic species that are changing the ecology of our region and threatening to replace adored local plants with lesser substitutes. Japanese knotweed, Russian olive, Asiatic bittersweet and Norway maple are villains that come quickly to mind, their names revealing their native habitats, while garlic mustard, wild chervil, goutweed and common reed sneak in with less obvious names. And there are dozens more.
People will spend many thousands of hours pursuing these aliens across the valley this summer. In doing so, are we following the 85 percent rule and really making a difference? Or are we following the 50 percent approach and just making matters worse?
On our farm, we struggle with glossy buckthorn and Japanese barberry. Both of these invasives grow around the edges of our fields and in woodland openings, supplanting witch hazel, used by New Englanders for centuries for treating fevers and rashes, and hophornbeam, know locally as iron wood for its great strength and utility in the age before steel was easily available. Both buckthorn and barberry grow into thorny hedges, making it hard to walk or even see ahead into the woods. Both species were deliberately introduced to North America and sold in nurseries, with the idea that their pretty berries and autumn color would complement the native landscape. Instead, they are supplanting it.
I want to emphasize that I am a willing foot soldier in the invasive wars. I have taken saws, loppers, weed wrenches and even herbicides into the woods in an effort to turn the tide and protect our native landscape, both on our farm and elsewhere in the valley. But increasingly, as the list of invasives grows ever longer and more pernicious, I’ve become concerned that we’re too often following the 50 percent approach — putting in a bunch of effort that’s not accomplishing much on the ground.
A case in point is Japanese knotweed, a bamboo-like weed that can grow 10 feet tall and that is already found all along the banks of the Connecticut River and its tributaries. I was part of a work party one morning that hacked its way down to the riverbank, only to pause for lunch and look upstream and see nothing but knotweed in all directions. The landowner we were helping wasn’t committed to maintaining the knotweed-free patch we had created, and when I visited the site only one year later, our morning of effort had vanished without a trace. Knotweed, like quack grass, spreads very efficiently via rhizomes.
What bugged me the most was that, even though we’d spent a fun morning in the woods together getting our hands dirty, we might have spent all that volunteer time in some other way that might have had a lasting effect, like building a trail or restoring a riverbank or maintaining a park. The opportunity cost of the war on invasives is enormous.
I’m not suggesting that we throw up our hands in defeat, though I think admitting that the war is lost would be helpful, since we’re never going to eradicate most of these species from most of our lands. Instead, we should concentrate our efforts in areas where battles can still be won, joining forces to apply the 85 percent solution wherever it will be effective.
Perhaps there is a section of riverbank with a particularly outstanding vista or an especially noteworthy assemblage of native plants that, with steady effort, can be preserved. Perhaps there is a pasture or area of woodlands that is still lightly infested and whose owner is willing to commit time and money to keeping it pristine. Perhaps there is a park or area of public land where volunteers will be willing to put in sustained effort over time. We should identify these places as soon as possible and throw all of our collective efforts into protecting them.
And then step back to enjoy the success we’ve had in these areas rather than lamenting the losses we were not able to prevent.
There’s a legend surrounding Odysseus, the Greek hero, that I find deeply troubling as a farmer. Odysseus, in an effort to avoid going to war, tried to convince his countrymen that he had gone insane. He took an ox and horse down to the beach and plowed furrows in the sand. After each pass, the waves lapped in and obliterated his work, yet he turned the team and made pass after pass, the accumulation of his hard work leading to absolutely nothing. If there’s a better image of futility, I don’t know it.
Whenever I grab the loppers and saw and head into the woods, I can’t help but wonder if I’m not joining Odysseus in plowing the sea.
Chuck Wooster is a farmer and writer who lives in White River Junction.