Wild Awake

Invasive Plants: Friend or Foe?

When I took the California Naturalist Training program a few years ago, I focused my capstone project on the problem of non-native invasive plants in the Lagunitas watershed. I had been volunteering for the Salmon Protection and Watershed Network working to restore endangered Coho salmon in local waterways, and invasive plants were seen as an impediment to this work.

After I completed my research, it was like someone gave me a new pair of eyes. I saw invasive plants everywhere. I couldn’t look at the landscape in the same way anymore. All I saw were hordes of invasive plants: scotch broom, periwinkle, English ivy, teasel, poison hemlock, Himalayan blackberry, thistle, pampas grass, eucalyptus, iceplant, cotoneaster, and more!

Riparian zones were some of the worst affected. But invasive plants were everywhere. Any place the land had been overgrazed, cleared, developed, or cut through with roads or wires. Wetlands. Wildlands. Backyards. Beaches. Parks. Roadsides. Farms. Forests.

Invasive plants were the enemy of native lands. They were aggressive, forming dense stands that excluded native plants, trees and wildlife. They lowered species diversity. They provided little to no forage. They were toxic. They created adverse conditions in the soil. They contributed to soil erosion along stream banks. They were a flood hazard. A fire hazard. They harbored invasive vermin. They needed to be controlled, removed, and destroyed.

The 2005 Interagency Task Force of Federal Government Scientists states that invasives are: “one of the greatest threats to the Earth’s biological diversity. America is under siege by invasive species.”  NASA says they are: “the single most formidable threat of natural disaster of the 21st Century“.

According to the Nature Conservancy: “invasive species damage the lands and waters that native plants and animals need to survive. They hurt economies and threaten human well-being. The estimated damage from invasive species worldwide totals more than $1.4 trillion.”

California spends more than $80 million on fighting invasive plants each year. The United States spends around $13 billion.

The war on invasive plants is big business.

When I saw these large numbers, I began to ask questions. Who pays for this war? And who benefits?  It turns out the Federal government pays for most of this war – your tax dollars at work. Invasive plants are controlled primarily using herbicides. The chemicals used are developed by the same companies that first developed them for use in human warfare. Dow Chemical. BASF. Monsanto. DuPont. Bayer. Syngenta.

The truth is that herbicides, largely untested and deadly poisonous, are being spread over our lands and waters, threatening the health of all life supporting systems, under the guise of an ever-expanding war on invasive species, with massive profits for a handful of powerful corporations with strong ties to government, and we are the ones who are paying.

After reading Timothy Scott’s radical book “Invasive Plant Medicine” I’ve come to the conclusion that this war is unfounded. What if invasives are serving a restorative, ecological function, one that we just don’t fully understand? What if permaculturist Toby Hemenway is right, that the spread of invasives is nature’s way of “throwing a green Band-Aid over ravaged landscapes“? What if engaging in a military approach to eradicating invasive plants is digging us deeper into ecological disaster?

A growing number of scientists purport that invasive plants prepare the conditions for succession. There is scientific evidence that they detoxify the soil, prevent erosion, clean the waters, restore biodiversity, and bring health back to the Earth’s ecosystems. If we take a long-term view, adopt a Gaian perspective, we could find that invasive plants are not the enemy after all, but part of a larger story of healing unfolding on the landscape.

Invasive plants appear in the landscape for a reason. They are there because we are dividing, disturbing and destroying the earth’s ecosystems. They are indicators of an ecosystem in trouble. Invasives don’t invade when ecosystems are intact.

Invasive plants aren’t the problem. We are.

We need to wake up to this truth, and put our energy into practices that support life on Earth, not destroy it. To do that we need to dismantle the ideological and physical structures that created this war, and shut down those institutions who are invested in killing the living earth for their own profits. We have to end this outrageous, rampant poisoning of the land and water, and let nature do what it knows best.

That doesn’t mean we don’t do stream restoration work to provide healthy habitat for the last of the Coho salmon. It means that we do this work knowing that these are damaged landscapes and poisoned waters, and that each invasive plant has a purpose, a role in healing the ecosystems we have torn apart. By carefully observing nature, and recognizing the innate intelligence of life, we might start to come into right relationship with the plant world, and our restoration efforts will become more effective over time.

In the words of Timothy Scott: “May we all come to our senses, and begin listening to these bountiful green teachers of the land, who speak with an ancient eloquence of deep ecological understanding.”


  1. Maricela Perdomo

    Thank you Raven for your insight!

  2. Pamela Gray

    A very interesting article that gives a completely new perspective on the issue of invasive species. Perhaps we can finally stop the indiscriminate pouring of poisons onto the earth in the false war in nature and let the earth heal itself over time.

  3. Jax

    While I disagree with the use of herbicides; there is a difference between invasive and nonindigenous species. Some introduced plants can coexist peacefully with their new neighbors and even offer benefits. However, some, like the invasive tamarisk bush that was foolishly planted along the Colorado River to “prevent erosion” about 70 years ago is invasive and harmful to the ecosystem. It is important to know which, and try to dig up the harmful invasive species.

    1. ravengray (Post author)

      @Jax, I completely agree that we need to continue with restoration efforts, and that sometimes includes removing invasive species in certain places, at certain times. But I do think it’s important to question assumptions and look a little deeper beyond the usual anthropocentric worldview. Damage to the ecosystems of the Colorado River have all been caused by industrial civilization.

      With respect to tamarisk, I highly recommend you read this: http://bioscience.oxfordjournals.org/content/55/8/648.full

      Scientists are beginning to realize the ecological benefits of tamarisk, and that if we freed the Colorado river, the tamarisk would not be flourishing as it is now.

  4. Anna Helvie

    I will read the book you cited. Don’t get me wrong, here in the Southeast, I have seen ligustrum take over, and I don’t like the monoculture any invasive can create. However, many of the invasive exotics here in the Southeast have documented healing or nutritional benefits. Lonicera japonica is being studied for anti-influenza properties. Elaeagnus (autumn olive) has some permaculturists harvesting and making sellable products out of its berries. The nutritional and medicinal benefits of kudzu are well-known. Yet, we prefer to just treat these plants as “the enemy.” Something’s not right about this.

  5. Tim B.

    This is one of the better things I’ve read in a while and hearing it expressed like this, it immediately rings true.

  6. Larry

    You think invasive a are OK and I would purport that you are a lost revolutionary!!!

    1. ravengray (Post author)

      I don’t think that invasive species are OK, rather I question the war that we wage on them, and whether there might be another approach to restoration and repair of our land base.

  7. Vicki

    Can you tell me what the name of the plant is pictured?

    1. ravengray (Post author)

      scotch broom

  8. Milton Dixon

    I’m glad to see this kind of thinking about the problem of invasives. Weather or not these “invasive” species are green bandaids or just happen to be I the right place at the right time, it bears repeating that humans have degraded every existing ecosystem on this planet. We are the cause and unless we change the way we see and interact with the world invasive species and change will be the norm.

  9. Ottilie Neser

    I notice that NOBODY in this discussion has mentioned biological control methods to suppress invasive plants that, without their natural enemies, replace indigenous flora. And from my own experience, it is not always in disturbed areas that invasive plants are a problem, they often go into prime, undisturbed conservation areas. Biological control has been vilified by people who do not know how it works and how researchers spend years to make sure the insect/pathogen is safe for indigenous plants.
    I agree that we should use poison only as a VERY LAST resort, and try to re-establish some sort of balance by natural means. It works.

  10. Juliet Thompson

    There’s another book that outlines the uses for “invasive” species, Tao Orion’s Beyond the War on Invasive Species, that I recommend. I have done lots of restoration work, and had to get an herbicide applicator license to do it for private landowners through the CREP program. I totally resented this, but I could also see the value of very selectively and carefully using small amounts of herbicide at times. Yes, industrial civilization has caused the problem, and as long as we remain populous at these levels, the issues will continue to exist, but to call that out is merely a point of view. Much good work can still be done. Here’s a link to Tao’s book http://proutinstitute.org/home/learn/bookstore/

  11. donna

    Human wage war on everything, war is destructive as if not more destructive than the original problem – not just with invasive plants. I have found that when you focus on restoration of the soil the native plants not only compete effectively but often nearly eradicate the invasives. It is the same with weeds in our garden. Instead of asking how do I get rid of it – start asking why is it here. Nature is not prejudice that is a human trait Nature allows what will grow to grow. Here they spray roundup on Japanese knot-weed – it dies and comes back stronger and spreads further. Before anyone told them it was invasive the same little patches stayed put but did not expand – since they have started spraying – killing anything that could compete as well – it has doubled. The environmentalists will end up killing the planet because they can not listen to the earth they want to “save”, only to humans and their studies. The truth we miss is adapt or die- the earth is adapting.


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