GardenRant welcomes back garden ecologist Nathan Lambstrom, in Part III of a three-part series discussing invasive species rhetoric, and the negative effects powerful war metaphors have had on the perception and management of exotic and invasive plant species in our gardens and greater ecoregions. The first installment explored the roots of this language; the second examined the tangible harm it can cause, and the last considers a more helpful way to think about, talk about, and interact with these species going forward. – MW
Over the last half century, the field of invasion biology acquired a vocabulary of war metaphors which inspired passionate action and were easy to communicate. The field grew as the message was spread; but as our understanding of how invasive species interact with novel ecosystems has grown, the hyperbole has become increasingly harmful.
Many ecologists, conservationists, and gardeners are advocating a shift in both the language we use about these species and the attempts to eradicate them at all costs. It is high time we move past the war on invasive species, abandon a militaristic vocabulary of pre-judgment, and embrace curiosity about these plants, even as we attempt to manage the changes associated with them.
If we dispense with the neat and tidy language of invasiveness, what are we left with? We still need to communicate about species that spread rapidly and exhibit competitive behavior; and it is still instructive to distinguish between species that evolved here and species that were recently introduced from somewhere else.
Passengers, Not Drivers of Change
One of the root problems of invasive rhetoric is that it gives too much agency to plants, framing them as insidious villains on the attack. To talk about them in this way ignores the conditions that led directly to their thriving: colonization and plant introductions; industrial agriculture; habitat fragmentation; ecological degradation; fire suppression; etc.
What we need is language that reflects the reality that these species are symptoms of a disturbed ecosystem, not monsters causing harm.
We have short memories. For instance, we see a forest with a thick understory of buckthorn and imagine that the forest was in a high-quality condition with diverse native flora in the not-too-distant past until the buckthorn came in, relatively recently, and took it over.
What we don’t see is millennia of careful management by Indigenous people that created many of those high-quality landscapes we imagine as natural (Rice 2025), and we don’t see the European colonization that put a stop to those practices.
Consider Land-Use History
Centuries of fire suppression, logging, grazing, plowing, and habitat lost to development (all major forms of disturbance) combined with the plant introductions created the perfect conditions for plants like buckthorn to thrive.
In most cases the native plant communities were lost long before the invasive species established a presence. When we blame the buckthorn directly, we are confusing correlation for causation.
The buckthorn didn’t create the damaged landscape or wipe out the native flora; it is an indicator of previously wrought damage. And if we do nothing to address the underlying conditions that allowed it to thrive or to reintroduce the plant community that was lost, removal alone is unlikely to do much in the way of restoration (Lambstrom et al. 2022).
An oak woodland with a rich understory of herbaceous native plants; an oak woodland with a dense shrub layer of buckthorn after centuries of agricultural land use and suburban development (author photo).
Remember Root Causes
Far better to refer to these plants with language that reminds us of their root causes and accurately describes their behaviors. When we call a plant “introduced” instead of non-native or the more troubling “alien” or “exotic”, we stress that the plant did not come here of its own volition. It was introduced to this environment as a direct consequence of colonization, and we would do well to remember the ecological impacts of colonization that have allowed that plant to thrive.
Learn Plant Life Strategies
To stress a plant’s behavior, we can return to our friends the ruderals (described in Part I). Ruderals, if you remember, thrive on disturbance, have a short lifespan, and produce copious seed. Most of the plants we traditionally think of as weeds can also be described as ruderals. It is one of three life strategies proposed by J. Philip Grime to describe plant behavior in his seminal book, “Plant Strategies and Vegetation Processes” (Grime 1979).
A modified version of J. Philip Grime’s life strategy triangle.
Plants are categorized based on how they respond to stress (e.g. lack of nutrients or water) and disturbance (plowing, grazing, fire, etc.). A plant that thrives on low stress and high disturbance is ruderal, like garlic mustard or the biennial black-eyed Susan. One that thrives on low stress (fertile habitats) and low disturbance is competitive, like mugwort or Canada goldenrod.
Competitors tend to be longer-lived and spread clonally to form large patches. Plants that thrive on high stress and low disturbance are stress tolerant (long-lived plants like saguaro cacti), biding their time in extreme environments until they’ve accumulated enough resources to reproduce. Most of the plants we think of as invasive fall on the ruderal-competitor spectrum.
Viola pedata, a native stress tolerator, establishes healthy populations under high stress, low disturbance conditions (author photo).
What Can We Say Instead?
My preference lately is to refer to these plants as “competitive introduced” species. I have colleagues who prefer “disruptive introduced” or “harmful introduced.” Some Indigenous conservation leaders prefer the term “displaced plant relatives,” as a way to honor the inherent value that these plants have as living beings that are sharing our home (Hernandez 2022, Wakaŋ Tipi Awaŋyaŋkapi 2021).
What all of these terms do better than “invasive” is more accurately describe both origin and behavior. Perhaps when we call a plant a “competitive introduced” species, as opposed to a competitive native one, it also reminds us that competitiveness or ruderalness are traits not restricted to introduced species.
A competitive patch of Canada goldenrod in a meadow should be managed much as a patch of introduced mugwort would be. Remembering that their behavior is linked to the land use context in which they live can help remind us that these are not evil monsters, they are competitive plants thriving in an abused landscape, regardless of origin.
Greenbriar, a competitive native plant that has filled this woodland understory following centuries of agriculture and grazing (author photo).
Looking Forward
None of this means that wild native plants in North America could all be replaced with “invasive” plants without consequence, nor is there any realistic likelihood of that happening. Native plants are extremely important and are the foundation of wild terrestrial food webs. I say that as often as I can and will continue to plant, promote, study, and enjoy native plants. I will also continue to advocate for a shift in perspective, away from pre-judgment of introduced competitive plants, and towards curiosity and thoughtful stewardship.
When I see an area with abundant knotweed, buckthorn, bittersweet, or garlic mustard (or any number of native competitive plants like grapes or smilax) I no longer see a landscape ruined by an aggressive interloper. I see a neglected ecosystem in need of care and careful stewardship.
The landscapes closest to us and most affected by us thrive when we develop a close, intimate relationship with them. That means taking a step back and answering clearly: What is the right goal for this place? What is feasible? What is the long-term plan? And sometimes: would I react differently to this plant if it were native?
Sometimes the answers to those questions will lead us to remove introduced plants and establish a new plant community. Sometimes simple observation will be the right course of action, watching to see how new ecological connections unfold. Sometimes the right way forward will be a more selective tending, a careful and loving gardening of wild spaces.
We are a gardening species. We have been moving plants around and tending them for as long as we’ve been human. That tendency has certainly created some challenges, but it’s also created a lot of beauty and ecological value, both of which are ignored or dismissed as unnatural by invasive species rhetoric.
I believe that we’re at the threshold of a major shift in the way we think about, speak about, and manage these species, but to paraphrase the plant ecologist Michael Yadrick, “we do not need a kinder way to talk about a harmful system; we need a new system.”
The way we’ve been taught to view invasive plants is unscientific and harmful, both rhetorically and in terms of real consequences for wild plants and animals. We ought to approach them with curiosity, as a unique opportunity to witness firsthand how new species integrate into ecosystems. If we look closely, we can develop a more nuanced view of plant ecology and see the chaotically beautiful ecosystems around us not as battlegrounds, but as opportunities to develop deep relationships with our neighbors in the plant world, no matter where they’re from.
Nathan Lambstrom, MS
www.gardenecology.us
Introduced rugosa rose and native Eastern redcedar forming a novel plant community in southern Rhode Island (author photo)..
References
Grime, J. Philip. Plant strategies and vegetation processes, and ecosystem properties. John Wiley & Sons, 1979.
Hernandez, Jessica. “Invasive Species as a Metaphor for Colonization.” Rewilding Magazine, 16 June 2022, www.rewildingmag.com/invasive-species-as-a-metaphor-for-colonization/. Accessed 10 Apr. 2026.
Lambstrom, Nathan, et al. “Low passive restoration potential following invasive woody species removal in oak woodlands.” Restoration ecology 30.4 (2022): e13568.
Rice, Stanley A. Forgotten Landscapes: How Native Americans Created Pre-Columbian North America and what We Can Learn from it. Simon and Schuster, 2025.
Wakaŋ Tipi Awaŋyaŋkapi. “Planting Moon in a Warming Climate.” Wakan Tipi Awanyankapi, 11 May 2021, www.wakantipi.org/wta-blog/2021/5/7/planting-moon-in-a-warming-climate-pzhkr-cfs8j-yeyez. Accessed 10 Apr. 2026.
Can you send me a link to Part two of this series? This is a great rant. My mentor at Vanderbilt was Dr. Elsie Quarterman, who shared with Dr. Katherine Keever the title of “Queen of Old Field Succession.” I had the pleasure of working with the ladies throughout the Gulf Coastal Plain when I was a grad student.
Thanks! Queen of Old Field Succession is an enviable title. I’ll have to read up on their work.
Here is part II: https://gardenrant.com/2026/07/the-war-on-invasive-species-part-ii-collateral-damage.html
And part I: https://gardenrant.com/2026/06/why-do-we-use-war-metaphors-to-discuss-invasive-plants-part-i.html
Thank you for responding. Somewhere I have a copy of Elsie’s reprint of the results of our research. Some sixty five years later I would be hard pressed to put my hands on it. Margaret Wrinkl mentions Dr. Qin her book “Graceland, at Last.”
I think you are absolutely right in your approach to our disturbed environment. Over the course of humanity’s medaling, the environment has been manipulated by revisionism. Gardeners thought it was great when John Bartram and Peter Collinson in the 1700s were ferociously exchanging plants and seeds across the continents; JD Hooker fueled the rhododendron frenzy in Europe, Palm Trees, that aren’t even native to Southern California, are iconic to its image, and immigrants were expected to bring the necessary healing plants with them to their new land. When the infighting dust settles, hopefully the revisionist attitude toward introduced species will be to embrace the well being of the layers life being sustained therein. In view of the continuous corridor of various plant life as we roll through the countryside, I feel this volume is more beneficial than the fragmented, patch work, pockets of native gardens intending to salvage rare species of insects. Say you’ve seen that Karner Blue butterfly cross your lawn, you plant a meadow full of Sundial Lupine to support it: not even a guarantee of success. We have to learn to work with what we’re given.
Nathan has said eloquently what I have been saying in my own way for nearly 30 years on Conservation Sense and Nonsense:
• Don’t try to eradicate non-native plants until and unless you understand why they are there and how they got there. If eradication does not address the cause for its existence, don’t bother trying to eradicate it because you won’t be able to do so.
• Don’t eradicate any plant until you know what it is contributing to the ecosystem and what its absence will mean to the ecosystem.
• If the method used to kill the plant will do more harm to the ecosystem and its inhabitants than the mere existence of the plant, put that important information onto the scales before implementing the project.
• Weigh the pros and cons. I predict that in many cases, the right decision will likely be LEAVE IT ALONE.
My advice applies only to public land, which belongs to everyone and every citizen pays for. In your own garden, feel free to do whatever you want. When visiting the gardens of others, keep your opinions to yourself. Spare them moralistic lectures about what they “should” be doing because it’s none of your business.
If I’ve understood correctly, viewing ‘invasives’ within frameworks of Grimes and succession is helping me to figure out how to manage a pain-in-the-neck part of my property that beats dousing the whole thing in herbicide or getting the big machines in here to scrape it all up and start over.
Previous owners of my house put down a thin layer of fine gravel by the garage and called it a driveway. I’ve used Grimes’ model of stress/ disturbance to enjoy what used to be unrelenting, unrewarding labor. – weeding my ‘driveway’.
1. Every wind- and poop-born seed seems delighted to start growing in a well drained medium such as gravel.
2. I’ve watched how earlier stages of plant succession set the conditions for the next stage. As early pioneer plants establish their root systems, they create wonderful soil that, when weeding, I try to roll up like turf (dislodging gravel as best I can) and toss rootside-up into pots – great compost. That soil made from accumulated layers of dead root mass actually changes the grade of my driveway. Is that why ancient artifacts are discovered meters below grade? Driveway as archeology.
3. Best of all, I’ve realized that our ornamental annuals are in the same class as the roadside weeds that move in after disturbance – short lifespans and copious seeds in low-resource, challenging environments.The driveway is currently over-run with zinnias, cosmos, nigella, lychnis, and tithonia. They set copious seed and re-appear the following year. Though several are not indigenous, most are visited by bees, birds, and butterflies. Perennial seed that has come in includes little bluestem, butterfly weed, and black-eyed susan. The driveway is surrounded by a thick turf that thins into shade when entering a property line of native trees and shrubs.
Weeding the driveway has become managing a garden. Trying to keep this environment in a ruderal ecology when it wants to move to a forest definitely takes energy, as any garden will. As for cars? If their drivers don’t mind rolling over some pretty flowers, no harm done.
Nina, I love this approach. I’ve been thinking of writing something up on a successional approach to weeding and I think you’re already implementing it! Sounds lovely.
Nina , you seem to have read and understand Grime’s methods. How do you think I could apply this to a field choked with mugwort? At least you had a seemingly blank palate to introduce plants into to do the work you intended. I once used an old gravelly driveway to plant various bulbs and iris and they absolutely loved the drainage aspect. I lived in zone 7.
I do truly hope that we are shifting away from a war on “invasive” plants. One of the things we talk about in psychology is how splitting (idealizing/devaluing; good/bad) as a defense mechanism covers underlying anxiety/dysregulation whereas curiosity is a sign of regulation. So it is very hard to be in black and white thinking and curious at the same time! I wonder sometimes about what the anxiety is underneath the native plant vitriol and the splitting around it (to the point where the moment anyone makes an nuanced argument counter they are accused of not supporting native plants and then need to repeatedly state that one can both be a devoted steward of natives *and* question our current narrative but this seems hard for some spaces to hear). And the moralizing that then attaches itself to this makes it even more difficult. I imagine whatever the underlying anxiety is, be it climate change or guilt for the general destruction we humans are creating in our ecosystems, it would be more helpful to all of us to address it honestly rather than hide from it by feeling superior to others and needing to call a plant evil. Thank you again for another wonderful article and the compassion and clarity you bring to this sticky topic.