Why You Should Care About Invasive Plant Species Removal
Or: Scapegoating native plant advocates for wanting to keep local endemic plant populations alive so you can feel better about how much you love an invasive plant species isn't a good look.
It was mid-March and we’d gone to the Great Smoky Mountains National Park for Spring Break. We’d been hiking on the Abrams Falls Trail for an hour or so, maybe longer because of all the stops to look at plants, and we were nearly to the falls themselves. We wound around a corner and I saw a seep was coming out of the side of the mountain adjacent to the trail—the perfect place for ferns and interesting plants growing in the nooks and crannies of the rocks, a place for me to stop and inspect for a few moments. And there I saw it, first my brain telling me, “Oh no, there’s Lygodium again! Damn it!”, cue heavy eye roll, and then my brain correcting itself, “OH MY GOD! That’s Lygodium palmatum!”
Lygodium palmatum is the native version of the genera of climbing fern that is swallowing native ecosystems in Florida and throughout the south. I’ve known about this species for a while but because I didn’t really dive into exactly what botanical species I might see during this trip, knowing we would be a good month early for most of the spring blooms, I wasn’t expecting to find this plant in the national park, much less this trail. I’d first come across Lygodium in its very invasive forms in south Florida where I once lived and worked and saw first hand the destruction that Lygodium microphyllum and Lygodium japonicum have done to natural areas. L. microphyllum is currently only found in central and south Florida for the most part, though I am seeing iNaturalist reports along coastal Alabama with plants coming in on nursery stock. It’s only a matter of time…
L. japonicum, however, is widespread throughout much of the Deep South, and while it doesn’t quite swamp habitats nearly as bad at microphyllum, it’s ubiquitous in almost any environment and will take over smaller footprints of habitat. I had a small plant of L. japonicum come up near my air conditioner outside a couple of years ago, I suspect it likely came from a nearby (0.5 mi away) fern nursery as I’ve had some other oddball things sprout, including an ornamental Peperomia one year. But it certainly could have seeded from spores from an unseen, nearby location along a creek side or park nearby, too.
There’s a growing, or maybe just vocal, cohort of folks jumping on what I want to say is a “pro-invasive” plant bandwagon but I wouldn’t even necessarily call it pro-invasive— it’s pro-all plants, anytime, anywhere. (I’ll refer to them as “all plants” from here on out.) And it’s an incredibly damaging campaign these folks are embarking upon when talking about invasive plant species on any one of the social media or writing platforms, including Substack. I think a significant component is coming as backlash from the native plant movement in the last few years, a natural mechanism that we see from any kind of movement in which there is a pushback on social change and advocacy. This latest wave in promoting and educating about native plants and ecological gardening is just one of many waves over the last 40 years, only this time we have everyone connected to their phones, replete with internet memes and social media to get the message out. Make no mistake, we’re still a tiny bubble of native plant enthusiasts. It doesn’t take long to step outside of your comfort zone to realize that. The vast majority of gardeners are still planting conventional horticultural offerings from the local nursery, with maybe a handful of whatever native plants are available that are reliably easy to grow. Most people cannot tell you what ecoregion they live in or anything at all about the habitat types of their area, even some of the keenest gardeners out there. Beyond that, it’s mostly a wall of green “weeds” to the majority of the population.
This essay was one that grew out of another essay I read here on Substack several weeks ago and it infuriated me so much I started drafting something almost immediately. I knew I couldn’t publish it as is because it was built so much out of anger at the mis/disinformation, so I took some time to mull it over, to come back to what it was that I really wanted to say. The author has continued to write about the topic and thus, here I am. Just as I think many gardeners, and even native plant gardeners, don’t actually get out and understand the ecology of their area, I don’t think these “all plants” folks are doing that either. And if they are, they are coming at it from a human-centered perspective: How can I eat this invasive plant? How can this plant make me money? What can this plant do for me medicinally? Etc.
In some aspects, those are appropriate questions to ask. For all of human history we have relied on plants for our medicines, for creating income, for putting food on the table throughout the year. We still rely on plants for these things but they come in different forms: monoculture fruit and vegetable crops, monoculture pine plantations, monoculture corn for ethanol, etc. This is where ideas like permaculture came into play, because on the surface it offers the promise of being regenerative with the landscape around you. But when you begin incorporating invasive species into the mix I’m not sure how regenerative you are actually being on the whole. How can you claim you are being ecologically responsible when you are allowing the spread of invasive species into nearby habitats, thus creating monocultures over time?
Nearly a decade ago I liked to listen to a gardening podcast called All Things Plants by the original founder of Dave’s Garden. The podcast has been defunct for a while now. In one of the episodes Dave and his wife talked about moving Chinese privet, Ligustrum sinense, from a bottomland on their property to plant on a berm near the road to act as a sound barrier for the road to the rest of the property. I almost lost it while listening and even went onto the forum to comment on how incredibly detrimental it was to even be giving people the idea to do that, beyond even just doing it themselves. Here was someone steeped in the horticulture industry advocating moving invasive plants around for personal use and yet, really, that’s just par for the course when we’re talking about invasive species and the horticulture industry. Most will bend over backwards to try to make non-seeding, non-native privets or Nandina (and insert other species here) that “won’t spread” instead of looking to find ways to bring to cultivation, en masse, native plants that work in the same manner and provide ecosystem functions to the wildlife native to the local ecoregion. Well, now your ‘Sunshine’ Ligustrum doesn’t flower which means it doesn’t even provide nectar for non-native honeybees! Good job!
(omg, I’m re-reading the post that started this all and am getting angry again…)
Driving to the Smokies back in March, I finally got to see first hand how bad Bradford pear is to other regions of the south. It’s planted in home landscapes in some regions of Texas more predominantly than others and I’ve seen it escape on occasion (we have other tree issues) but as we made our way from Mississippi to Alabama and then started turning north toward the GA/TN border I was just astounded at the blooms—because the blooming trees gave evidence of just where they were located. And they were everywhere! It really hit me in the face how much of a problem they had become in that particular region of the country. Sometimes you can’t believe the extent of an issue until you see it first hand, and see it I did. Every region has its invasive species issues due to soils, temperature, disturbance, and other factors. We should take the issues seriously because even if a particular invasive isn’t a problem in your state or county now, give it 10-20 years and it certainly could be.
One of the major issues surrounding invasive species management is the use of herbicides to remove invasives and some people don’t even like the thought of brush hogging. I get where people are coming from with herbicides because we have such issues with their use in our crops and the amount of pollution and detrimental effects to the environment they cause when used so broadly. Everything from affecting amphibians to causing phenomenon like the Gulf of Mexico’s dead zone. There’s a valid reason to be upset about that when we have historically had a very bad track record with it. But every ecosystem restoration ecologist will tell you there is a significant difference in broad spectrum spraying using far too much product in ag settings compared to targeted removal of species in a relatively small footprint for habitat restoration, using the appropriate label mixing recommendations. There’s a big difference in collaring melaleuca trees in south Florida or Chinese tallow throughout the entire south, and targeting each individual tree with herbicide than aerial spraying crop fields.
A couple of weekends ago I made a trip to a favorite natural area in Fort Worth, Tandy Hills Natural Area. It’s remnant prairie at the doorstep to downtown Fort Worth, surrounded by subdivisions, an interstate, and it certainly hasn’t been “natural” there in more than a hundred years. My parents grew up nearby. The City owns the park but Friends of Tandy Hills (Don and Debra Young were on the podcast when it was going) does a lot of the educational outreach and communication, and did most of the legwork in saving the park from being a site for drilling back in the 2000s when DFW was in major play for o&g exploration. They also managed to raise enough funds to get the Broadcast Hill expansion to the property a few years ago. They do a lot of really good work! One of their other projects they’ve been working on with the City and other groups is getting invasive privet removed from the property, along with other invasives such a nandina.
Meanwhile, Young said he is hoping the sight of workers mowing down large swaths of brush won’t alarm visitors or passersby.
He promises there will be a payoff in two or three years to the temporary environmental damage.
Eventually, Young says the clearing will give way to native wildflowers and grasses returning.
“Underneath all this privet is a seed bed of native plant seeds. This is a chance to recover some of these areas.” - via Green Source DFW
During this trip a few weeks ago I saw some of those brush hogged areas. And guess what? The prairie is coming back. Areas that were swathed in privet, red-tip photinia, and other ornamental exotics and invasives that were choking out native vegetation, are now cleared and those native prairie species are coming back!
To the untrained hiker, privet is a cheery sign of spring on the trail. But to those who care for our natural areas in DFW, it’s a formidable foe.
"There's a greenbelt in my town,” said naturalist and native plant expert Carol Clark. “The trail seems green, leafy and inviting at first, but as you walk in, you realize because the privet grows so densely that there is no place to put a foot down anywhere but on the path.”
And it's all surrounded by dead silence, says Clark.
“No buzzing of insects, no flutters of wings, no birdsong. There are no small scurryings, no animals in sight. There is nothing here but privet."
Richard Freiheit, restoration manager at Lewisville Lake Environmental Learning Area, has a harsher term for privet-infested nature:
"It's a green wasteland." - via Green Source DFW
This second article from Green Source DFW, written by Wild DFW’s Amy Martin, chronicles a different preserve in the DFW area and the impacts privet has had on it as well as outlining the methods of eradication used to get the results desired, which do eventually come. Just one of many natural areas suffering the effects from bad decisions made by gardeners and the horticulture industry, inadvertently or not, over the decades.
An Instagram acquaintance, Canaan Sutton, was sharing on his Stories recently some photos of King Ranch bluestem (Bothriochloa ischaemum) monoculture on a former prairie compared to what the habitat should look like. I struck up a conversation about it with him because the photos were showing exactly what I wanted to portray in this essay, that we lose biodiversity when we have invasive species, not gain biodiversity, despite what many of these “all plants” people want to portray. Canaan said I could use his photos and share the post that was in his feed regarding KRB. KRB is a notoriously invasive grass here in Texas, of course originally introduced by way of agriculture around the King Ranch area of south Texas. I think many people don’t even realize what it is because it is just a wall of grass and if you look at it during the right time of year, it does have a nice golden tone and it isn’t ugly but once you see it for what it is, you change your tune. As the link above says, “Like other invasive plants and trees, it outcompetes native species and alters the ecosystem, reducing the diversity of species. KR bluestem is associated with the loss of native grasses and wildflowers, and a corresponding loss of insect and bird habitat.” It’s done a number on quail populations.
Here’s Canaan’s photos and post:
A comparison of a wonderfully diverse shrub/scrub area in the rolling red plains, directly across from a field plowed for grazing or cover at some point, dominated by the invasive grass King Ranch Bluestem (Bothriochloa ischaemum var. songarica).
Whether because of shallow sandstone or slopes I’m glad the area in the first picture persists, just this spring we catalogued about 32 species a square meter in some areas, vs >98% BOISS in the other pasture.
The myriad ecological interactions that can happen in the more diverse zones are why managing invasives is so important, and is key to the resiliency of these landscapes into the future.
I am sure “all plants” critics would say, yeah, of course the KRB area looks like this because of the plowing and grazing, but some of these people are the same folks who use regenerative ag as a reason to run cattle over places like the first photo. But as I elaborate in the next paragraph, the KRB field isn’t going to miraculously look like the first photo ever again without human input to fix it.
The response to these types of management issues with invasive species from “all plants” people is really we should do nothing—no herbicide or mechanical removal, or it’s the Magical Thinking of “The Earth Will Heal Itself”. Yeah, sure the Earth will heal itself on a geological time scale but humans don’t deal in geological time scales. We can’t afford to. The other way to try to make it all go away is the other Magical Thinking of willing it away and accepting the habitats have changed since time immemorial. It’s basically throwing your hands up and saying, “What’s done is done.” and moving on. Or using the excuse that there is some disturbance and blaming the action and not the consequence. Or my personal favorite, “Humans have always moved plants!” No, Felicia, not at this scale and at this pace. Yeah, it probably explains some really interesting disjunct populations of plants but it’s not a great excuse to live by as a reason for just accepting invasive species and their consequences.
Unfortunately the cause of most of our current invasive species problems is our human urge to grow plants, no matter where they come from. We have imported and exported plants across the globe at an amazingly rapid scale and pace since 1492 and even when we have the foresight to see how problematic they are in certain regions, we aren’t banning the bulk of them or it’s left up to individual states, counties, or cities to ban certain species. And then enforcement is difficult or non-existent. Or we have the bend-over-backwards horticulturists who attempt to breed out the reproductive parts because we’re so hung up on keeping hold of some plant because it either makes too much money or we gardeners can’t bear to be told no, we can’t have that plant anymore. Are we really that selfish?
(yes, yes, we are if the last four years have shown us anything…)
We do have a choice, here. There are native plant options that are continually overlooked and fill in many of the niches gardeners are looking for when they continue to reach for non-native plants. But they can’t buy them if they aren’t offered for sale. They won’t buy them if magazines or social media feeds aren’t talking about them. As I’ve outlined in many essays in the past year, most of our native plant movement failures come to head because of a lack of will in the horticulture industry. It’s too convenient to continue to propagate the easy stuff that makes money fast instead of doing the right thing. We can easily say no to every Nandina/Nandina cultivar being sold—and stop propagating it totally. We can stop recommending Vitex as an option above native alternatives, depending on ecoregion. ‘Sunshine’ Ligustrum can give way to dwarf yaupons and other non-native privets can be replaced with native hawthorns or our native privet species, Forestiera sp. That all seems too simple, though, doesn’t it? It’s even easier to just to hold your hands out and shrug ¯\_(ツ)_/¯ and proclaim native plant advocates the backbone of the problem because you don’t want to look too hard at the issue. It’s even more easy to do nothing because that gets you off the hook for taking any accountability.
I’m (not) sorry, but I’ll take well managed centuries old trout lily populations on remnant prairie any day over privet choked prairie that has such negligible value for wildlife if it means we have to manage for invasive species via chemical or mechanical means. I’m not willing to have local extirpations because “all plants” enthusiasts are willing to throw in the towel based on half-hearted valuations on what past humans may or may not have done with regard to moving plants. And you shouldn’t either. We live here *now*. We know better now.
I think this topic deserves more attention so I’m going to end here and return again soon with more Deep Thoughts. I’ve started reading further into some examples some of these “all plants” folks like to habitually use to further their arguments and I’d like to read those more and read some counter evidence and return with more in a few weeks. I fully realize this is a complicated issue in some manner, but in some ways it really isn’t. We’ve just chosen the easy way out.
If you’ve been reading the newsletter for any length or time or listening to any of my podcasts I produced over the years, you know I am not a strict native plant gardener, though I have slowly been morphing to native plants more and more as we work to grow out our 1.2 acre yard. There are species I grow because I know they aren’t invasive or don’t have invasive tendencies and there are species I will never grow because I know their tendencies (looking at you Ruellia simplex). We learn, we do better. Some things are out of my control, such as the colonization of taro along our pond shoreline because it is throughout the entire watershed. But we do remove it from our portion of the shoreline and our shoreline is all the better for it.
A few folks I’d suggest following on social media for native plants and invasive species education, if you don’t already:
Instagram:
Plants.are.people.too - excellent reels and commentary from New England Botanist Tom Groves.
lilliumbyrd - Lilly Anderson-Messec, botany from the Florida Panhandle and Director of North Florida Programs for the Native Plant Society of Florida.
wildplantculture and wildridgeplants - Jared Rosenbaum is a botanist who does native plant ecological restorations and runs a native plant nursery. I highly recommend his book Wild Plant Culture.
crime_pays_but_botany_doesnt - Joey Santore, botanist, wants you to Kill Your Lawn, definitely not for everyone but you’ll almost always learn something!
I follow a ton of botanists and ecologists and have been wanting to write a post on various folks to share here and I think I’ll leave it at these four for now and write that other post up separately.
I’ll pause for invasive species for a newsletter or two because my next newsletter is going to be on an almost equally, if not more, contentious topic: the obsession with monarch butterflies. And it probably isn’t going to go how you think it is going to go!
Misti writes regularly at Oceanic Wilderness and On Texas Nature and can be found on Instagram at @oceanicwilderness. She hosts one podcast, Orange Blaze: A Florida Trail Podcast, and formerly hosted The Garden Path Podcast.
I think the reason many people are taken in by arguments from the "all plants are good" people is that they aren't out there witnessing how bad it is. They haven't had the experience you described when you saw the masses of callery pears. They see the debate as mostly theoretical, something that should be decided based on ideology. The fact that the arrival of certain invasive plants tends to mean less diversity and in some cases reverting to near monocultures is not understood at all.