Hopewell, NJ, August 2021
I was pulling stiltgrass out of one of the gardens the other afternoon. It came out easily. It’s not yet ready to seed but still was higher than the other, more desirable groundcovers; the creeping jenny and the pachysandra that have been coaxed out from the overgrowth over time. It was only lightly rooted, like stiltgrass is, so a single sweep of my arm could pull out quite a bit.
Nearly everyone knows what Japanese stiltgrass is, I suspect. It’s one of the most pervasive and most recognizable invasive species, and it’s been around long enough to become familiar. One of its other common names, packing grass, gives away its likely source of introduction, packing material for shipments from east Asia, where it’s native. It’s a short-leafed grass with long stalks, not particularly high but high enough that it can suppress other ground-layer vegetation, blocking out the light and choking out access to the soil. Once it gets in, it’s only a few years away from becoming a ground-level monoculture, and it grows like crazy even in inhospitable conditions. If you don’t know what I’m talking about, the next time you go for a hike during the warmer months, once you’ve left the trailhead and moved under the forest canopy, look out across the ground. That lovely light-green grass that spreads out in the shade between the trees as far as you can see? That’s stiltgrass.
We’re close to its northernmost spread, and it’s pervasive throughout the state. It’s widespread from a little further north into New York and down much of the Eastern coastal south into Florida. It’s so pervasive now that it might be hard for some people to image a forest floor without it, though a few hours’ drive from the coast into the interior will bring you to forests where it has not yet taken root. There the forb layer of the forest is surprisingly bare and punctuated by things like the clubmosses we should be but aren’t seeing here. Stiltgrass isn’t entirely to blame for the lack of clubmoss: human activity has hada role, as with stiltgrass introduction, and one based in commerce as well. Before stiltgrass appeared and then as it spread throughout the southeast, people were picking the forest floor clean of fan clubmoss for Christmas decorations. Nearly depleted, it has grown back where it can, but where the stiltgrass is, there isn’t anywhere for it to grow. Stiltgrass is extremely shade-tolerant and will hold any space allowed to it.
Human activity has another role in stiltgrass monoculture. The suburbanization of much of the forest land on the East Coast has driven up deer populations by removing predator habitat. And deer won’t eat the stiltgrass. If you want to know why, try it yourself. Eating stiltgrass is like chewing sand – very unpleasant. There are apparently high concentrations of silica in the grass’s leaves. I think it’s easy enough to imagine liking the things that deer do like to eat, like flowers. I’m bitter about not being able to grow roses by the side of my house because of the deer, but seeing roses in bloom, I’m in perfect sympathy: I’d want to eat them too. Leaves and shoots, I can imagine as the equivalent of a bitter but nourishing salad of field greens. Anything that’s not stiltgrass and manages to thread its way through the underlayer to get enough light to grow, the deer eat quickly and thoroughly.
I’ve wandered a good way from my point, like the deer looking for fresh sprouts, but we’re looking for different things: I’m holding on to the idea of invasive species in my head. What do we do in the end about stiltgrass? Not much. As I said, it’s so pervasive along the coastal Southeast, that most people living in that part of the continent probably couldn’t imagine a forest without it. Kudzu gets more attention as a widespread and emblematic invasive species, I suspect, but kudzu’s a bit more localized in the warmer states and considerably more destructive – though kudzu is making headway into New Jersey as temperatures here and everywhere continue to rise! Stiltgrass now is simply a given. If there’s a forest floor, or an untended shady lot of land, there’s a carpet of stiltgrass. And that’s the case with a lot of invasive species. Sure, there are coordinated efforts to address the spread of many invasive species, whether its eradication of specific invaders in delicate ecosystems or encouraging gardeners to prefer native species and their variants rather than potentially invasive imports. There are hunting, cooking, and eating competitions for nutria and for lionfish. Recreational anglers are instructed to kill snakeheads on sight, and they’re reputed to be quite tasty as well. But some invaders are just too prolific for us to hope to eradicate, or even have an impact on their population. Stiltgrass is like that. There’s no point sending people into the woods to pull it out. There’s simply too much of it.
And there are too many spotted lanternflies where they’ve taken hold. Wherever they are, they always seem to arrive in quantities of “way too many.” And this may be a heretical position this early in the invasion, but we may find the spotted lanternfly is an invasive species that will move beyond our abilities to eradicate it. Anyone walking about the Delaware River last summer encountered massive clouds of them crawling over plants, chiefly the also invasive ailanthus trees that are their preferred host, and those clouds would send out a reckless flier or two to test out the adjacent flora every second or two. Far too many to swat, or spray, or capture in a kill jar, or whatever method you’ve been encouraged to use. A decade ago, it was the invasion of the brown marmorated stinkbugs, which were especially annoying since they seemed to appear in massive quantities indoors. Other areas on the North American continent are dealing with the stinkbugs now, and that seems to be the stinkbug rhythm – a massive influx that annoys and alarms for a few years, and then isolated individuals here and there, with a record of crop damage in their wake. That may turn out to be the lanternfly rhythm. Already some areas that were inundated last summer are wondering why the lanternflies haven’t returned in the same intimidating masses, though it may be that those areas are just a couple of weeks away from discovering that they’re still peak lanternfly after all. I found myself hoping that I wouldn’t again see clouds of them in my yard – we were out stomping and swatting quite a bit last year and even enlisted some of the neighborhood kids in the slaughter, but it wasn’t easy, and it seemed like for every one we splatted, there was one that took off and flew out of sight, an insect refugee transport. I was wrong, though, they’re back again.
It may turn out to be a rhythm like the ailanthus tree, a preferred host for the larva of the stinkbug as well the lanternfly. The tree, also known as Tree of Heaven for reasons that escape me, is another native of east Asia that’s become endemic. A constant in any unmanaged plot of land, it grows quickly. Very quickly, though not as quick as bamboo. It’s not a totally unobjectionable tree, certainly not from a distance. They have longish spear-point compound leaves in rows down long stems and look enough like a walnut tree that they can be easily mistaken for one. About this time of year, the greenish-yellow fading to reddish-orange sprays of flowers and fruit are evident on the female tree, much different of course, than the walnut’s green baseball. Up close, though, and over time, their objectionable qualities are hard to ignore. They take root anywhere they can, and like weeds have an affinity for disturbed ground. You have a year or two to remove them, but if you sleep on it, they quickly become a massive or expensive chore to remove. And they stink. The crushed leaves or the split wood smell horrible. In Mandarin the tree is called chòuchūn, stinky ailanthus. (This is funny to me because the chòu that means stinky is the same stinky in chòu dòufu, or stinky tofu, a favorite streetfood from when I lived in Taiwan, which lived up to its name but was quite tasty nonetheless.) Ailanthus roots exude allelopathic chemicals that inhibit the growth of other vegetation around them that would compete. So, yes, unpleasant. And a constant presence at the horizon of any managed space, or in the unmanaged interstices, waiting for a change in attention or effort to take root and take over.
The potential for crop damage or threat to desirable trees from lanternflies hasn’t yet fully materialized, though it still may. In the end the lanternfly may prove to be an endemic destructive pest, or an occasional destructive pest, or maybe just a seasonal or occasional annoyance. There are rhythms at work, some small and local, some massive, some annual, and some over a very long period of duration that is almost unimaginable to the human mind. I think that at some level we all appreciate that this is Nature in the abstract, larger sense, and we appreciate that nonnative invasives are signs of shifts in any given ecosystem.
In David Lowery’s The Green Knight, the recent and very excellent dramatization of the Arthurian poem Sir Gawain and the Green Knight, the characters midway through the film stop to engage in some metacommentary, pondering why the villain is green. Gawain points out that green is the color of life, and this is the answer we’re expecting. The Green Knight is, we all know, emblematic of the power of the vegetative life, a figure that has appeared in British arts and literature from the Green Man through Tom Bombadil. The lady of the manor at which Gawain is a guest, and whose presence is both enticing and discomfiting to him, counters that red and not green is the color of our own lifeforce, the color of lust.
Green is the color of that other life, that life that is not our life, but that life which always threatens to cover us over, to ruin our efforts with vines or moss or grass, to obliterate us and our memory. That force which we’re constantly fighting against to maintain our space; that life that is here before us and will spread out and cover over our works when we’re no longer alive to swipe it away.
We tend to think of the rhythm of nature as being that comfortable agrarian annual cycle through the four seasons and back again, and that our life has that same cyclic element. From birth to growth to senescence and then back again, at least back for the succeeding generation. But there are other rhythms: many of us experienced earlier this year one of evolution’s weirdest and most precise rhythms, that of the periodic cicada. But maybe rhythm doesn’t cover it fully: it’s a movement sometimes that includes periods of activity followed by periods of stasis, and then activity again. Or there’s a constant pressure into one direction until there’s not. Stephen Jay Gould coined the term “punctuated equilibrium” to convey his view of an evolutionary process that moved at rare occasions with sudden forcefulness when pressures required it but mostly not much at all. This was to oppose the conventional view of a steady, slow progression throughout. That might not be far off from how species become introduced into an ecosystem. People tend to think of nature when it’s undisturbed by human activity to be in some state of harmony, but here we may be guilty of imposing our own values. Ecosystems tend toward a complex state of tension, in which an advantage of one species drives the development of countermoves from that species points of contact with the ecosystem. In many cases those countermoves establish a tense equilibrium, and in others the countermoves may not fully compensate, and there is a glacial or a rapid transformation of that ecosystem’s character as a result.
Sometimes the glacial transformation is literal: one of my favorite stories of forest transformation is the displacement of native North American azaleas and rhododendrons into the mountainous regions of the Southeast when glaciers occupied the northern lowlands where the plants had previously spread. It was in the now ancient mountains of the Southeast that the rhododendrons found a climate analogous to the regions that had become covered in sheets of ice, and when the ices retreated, the rhododendrons were geographically isolated high up on the hills instead, trading altitude for latitude. Of course the story doesn’t have a happy end. The Appalachian region is becoming rapidly less habitable to the plants as climate change heats up their refuge and cuts off any avenue of escape.
At some point an invasive is just a native with a shorter history in that place than its ecological siblings. And sometimes clinging to the invasive narrative is just rude. Think of starlings. We’ve all heard now how European starlings were introduced to the continent a little over a hundred years ago when Shakespeare enthusiasts released a small flock of them in Central Park in hopes that all the birds mentioned in Shakespeare’s plays would someday find a home in North America. (I’m still waiting for my nightingales and my skylarks.)
Starlings are here, and they’re here in fantastically great numbers – something they’re justifiably famous for, and they’re not going anywhere. Some have suggested, and I think there’s a lot of merit to the suggestions, that our reluctance to embrace them as natives has a lot to do with narratives about immigrants and blackness and less to do with stories of ecosystems and equilibriums. Some invasives we seem to have agreed to forget that they weren’t always with us in this region or this continent, like earthworms. They’re so familiar and loved as composters, fishing bait, and friends of children, that we’ve forgotten how destructive they can be when they loosen the soil in old-growth forests, endangering the larger trees by weakening their ability to withstand strong winds, that is, if we had ever bothered to find that out. Maybe was only something that foresters have ever paid attention to. But it would seem silly now to want the worms gone.
We’ve moved on as a culture from the narratives of unrelenting vegetable threat and invasion and the ivied-over graves that the Green Knight represents, but as we’ve expanded our sympathies to the surrounding natural processes that we encounter intimately or imaginatively, those local ecosystems, have become part of our own story. We identify with them: they are us, or stand-ins for us. We cling to narratives of our association with a local ecosystem, and want to believe that we fight as hard as we can against that ecosystem’s eventual disappearance under a light-blotting alien invasion as if it were our own lives and works at stake. Part of that may be delusory – this ecosystem is not our own, has no love for us, and it is our own force that keeps it from eradicating our efforts and our lifeways.
Think of a building that’s been unoccupied and untended for a few years. Now consider it a few years more. And this ecosystem is not a thing so much. It is a recognizable node of pressures, antagonisms, truces, surrounded by a permeable and temporary boundary that shifts in location and in what it allows in and out, and to what it will fall helplessly victim, perhaps, but node that is a moment only in a long, long process. And here’s another angle: while we’re identifying with our place as being an inextricable part of us, what hasn’t fully entered into that story is how much the threat is us. It’s not just the direct but the indirect impacts that we have – the deer, the stiltgrass, the starlings, the weeds in our gardens, and so on, those are all consequences of choices we’ve made as much as the pollution, the concrete, and carbon emissions, and so on, and so on.
This may be cliché by now to mention, but it’s still not being said often enough. The spotted lanternfly and its ilk are the least of our worries when it comes to inexorable rhythms of the natural world. The steady pressure of climate change has already caused some of these tensioned equilibriums that anchor ecosystems to buckle and some to snap, and it is by now evident that there is going to be some significant ecological activity and even collapse that will rapidly alter most areas on the planet before and if we manage to get carbon emissions under control. Will it bad? It’ll likely lead to decreases in biological diversity, which any evolutionary biologist can tell you, is, yes, bad. But will it be bad for us? Hell, yes, it’ll be really bad for us. So what about the stiltgrass and the spotted lanternfly? Yes, absolutely you should kill lanternflies, especially if you’re trying to keep them from taking root in your yard, or if you’re concerned about orchards and vineyards in the area, or just to be civic-minded. But you shouldn’t be surprised if years down the line people recognize that there’s just no reasonable path to eradicating the insects because there’s so many of them, or if suddenly they cease to be noticeable, or if it is just a dull seasonal duty to keep them off certain trees in your yard or favorite park. Look, there’s molecular traces of human activity now on every single square mile on the planet. If your definition of wilderness is that which is untrammeled and unaffected by human activity, then wilderness is gone, never to return to the planet. It may seem arrogant to pick and choose who stays or who doesn’t in any given ecosystem, but that’s a role we accepted long ago.
It is certainly arrogant to assume our choices are all that will matter now. We have a responsibility to sustain life, and to allow its flourishing. Without the wilderness, we’re more or less stuck with our respective gardens, figured as small and individual or as large civic preserves. Right now, the stiltgrass, the starling, and the lanternfly are our co-gardeners. You don’t have to let them in the garden gate (except the starlings – those you do have to let in and care about), but they may have their run of it in the end.
Donald is an amateur naturalist, a writing instructor, and a university administrator at Rutgers.