Challenging what we think about invasive plants


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"Don't Sweat the Invasion" is the attention-getting title of a conventional-wisdom-knocking article on that we somehow missed when it was first published last year.  Thankfully it was republished in Landscape Architecture Magazine, where it naturally provoked a few letters to the editor.

The author names a few scientists who are "challenging what they consider old prejudices about 'alien' species.  They point out the inevitability of change and the positive roles that nonnatives can play in ecosystems, while describing eradication projects as often wasteful and even counterproductive."  The prime example given is the invasive tamarisk, which turns out to be the favorite nesting site for the
endangered southwestern willow flycatcher.

The article proceeds to even hotter topics, like challenging "native" and "nonnative" distinctions as meaningless, proposing a difference between harm and change and, on the other side, debunking the nativist/Nazi comparisons.  Fun stuff!

Mother Nature proves once again to more complicated than we think she is.


  1. Thanks for the great read with my coffee this am! Native, not native where do you draw the line? Is it native to your city, state, region, country? What about native plants that are aggressive and will take over do you not plant them because of that or do you let nature take it’s course. Gardening in it’s very nature changes it’s surroundings. If you go in and dig up everything that isn’t native and replace it with all native plants is that better? Have you done a favor or brought harm to the balance? I plant with nature in mind. Will it feed or house someone? After that is this plant something that would be aggressive and take over areas that I don’t want it to. If the answer to that is yes, I probably won’t plant it, even if it is native. This isn’t a matter of good verses evil, it’s a matter of being sensible and thoughtful of what you are doing. Though, that should be the case in everything you do, not just gardening..

  2. And what about the threatening of species because exotic invasive plants come in and out-compete them? Kudzu, Eucalyptus, Pampas Grass, Scotch Broom, Bindweed, and the Eurasian grasses that literally destroyed the California grasslands except for a few serpentine pockets, are at the top of my list as some of the most destructive plants ever to be introduced to the U.S. While some invasives aren’t as serious, there are some that are outright disastrous.

  3. Don’t forget Himalayan Blackberry, the Kudzu of the Northwest!

    I grow both natives and non-natives in my garden, except for the aforesaid blackberry, scotch broom, and bindweed which are removed on sight. Hell, if I see the native horsetail, I pull that on sight, too.

  4. I tend to think in terms of ecosystems. Things that provide a positive role I leave alone, those that are being thugs I kick out. I’m planting more natives both because I like the look and because the ecosystem needs to be sustainable. I do a lot of permaculture, sustainable landscaping, and finding the right plants for my local conditions that survive without a lot of special care or extra water.

  5. This Slate article articulated everything that I’ve been thinking about the whole native/non-native debate and I was glad to see some scientists are seriously making the case for a less knee-jerk approach. There’s a big difference between trying to contain and control seriously damaging invasives and just trying to turn back the clock on an ecosystem. That statement about understanding the difference between “harm” and “change” is really the crux of the issue.

  6. As a southern Californian, I know that Arundo donax is bad, bad, bad, however, as an oboe player, I have another view…. (i.e. necessary, necessary, necessary)

  7. I lived on the island of Maui for twenty years. The native ecosystem had been obliterated and replaced by immigrants, deliberate and accidental long before I arrived. In those twenty years I watched a continuing stream of new plant, animal and insects species arrive. Some arrived in a pestilent fury, hated and feared, targeted by the state for eradication or control. Others slowly blended in, ignored and became kama’aina without a fuss. The changes caused by the hated and the ignored could be of equal measure. Some group interest had to be offended before any new immigrant was called foul.

    Nature did what nature does in all cases. Looked for and found a new equilibrium with the ingredients on hand. Worldwide economic collapse resulting in the end of globalization, free trade between continents and international travel is the only thing that will stop the inevitable progression towards a more uniform planetary species distribution.

  8. I thought the Slate article was inane. It implies that the argument is as black and white as its series of counter arguments.

    Come. On.

    The knee-jerking belongs to the media. Most gardeners I know lack orthodoxy. We can tell the difference between Kudzu or purple loosestrife and garden variety non-natives. And enough with the Hitler hysterics! This is just a rag’s way to stir the pot -which is all that these articles are good for anyhow, because they present no science and lack depth. Articles such as this simply present a useful premise for people to extract from their delicate egos any sense of responsibility the next time they consider planting purple loosestrife.

    Yes, we are nature, yes we desire nature to be what we want and or need, and yes, conservation is about us as much as anything else. But we’re bright people, we can make good choices, we can have our natives and non-natives and not pretend it’s an all or nothing game.

  9. Now to call burning bush invasive, E. alatus, is a oke. This plant grows at a snail’s pace.

    Also the invasive nazi’s labeling barberry invasive is not quite true. Many species are perfectly non inflamatory in the gardens. Do us a favor invas-a-vores and qualify your tags or you will relegate your kind to the compost heap.

    The TROLL

  10. I like to believe I am broadminded. 🙂 Several yrs ago I wrote an article about garden plants that are both medicinal and ornamental for a herb magazine. Purple loosestrife matches this description. My editor was horrified and removed purple loosestrife from the story, even though my own experience was to the contrary; I had planted 3 plants at my pond’s edge in Atlanta (sacrilege?), yet after 1 season it had declined and only one plant remained. Exotics are not always invasive.

  11. Yes and drilling for oil off shore is safe now.
    While I actually agree that you can not stop this world wide expansion of change in the dominate species of flora and fauna,still I want very much to see some area natives survive. We helped eradicate so many we can also save a few.

  12. Probably we ain’t seen nothin’ yet, as climate change puts all species through an accelerated process of change and migration (something that has been happening since there was a planet). But we humans as a species are in the unique position of being able to make intentional changes in some cases, and prevent some in others. I know our nation’s agricultural industries are very interested in preventing select invasive insect and plant species from entering and getting established, so as not to interfere with food supplies and ag business in general. Maybe someday we will learn how to anticipate and work with the global changes, but that day is not now, for sure.
    We are also unique as a species in that we can survive in just about every climate on the planet, unlike most other species. But we seem to insist on bringing technologies and habits from one area to the next, which doesn’t always work so well.

  13. I suppose it depends on how the invasive plant species gets there. Plants that spread naturally are just doing what nature intends. Ofen the local ecology adapts. It is when we (people) introduce something entirely alien that things tend to go wrong.

  14. The reason, Master Troll, that many species are not invasive in gardens, as you put it, is because you are there doing the work of people, pulling things out that you do not want and planting hardy competitive species in areas designated for them. If we did actually garden every square inch of the earth, I’m sure we’d only have the plants we wanted where we wanted.

    My father-in-law resents any and all governments. Knowledgeable of the Minnesota Loosestrife ban, he often threatens to plant it in the government protected wetland on his property. Cutting his nose to spite his face?

    Don’t we understand that there is a difference between our perception of events and reality, Gardengeri? Georgia has not seen mass stands of loosestrife yet. But after your gone, Georgia will or won’t and you’ll have something to do with that.

    Man, okay. You win. Plant what you want. Who cares, I’m so tired of the same old conversation.

  15. There are profound ecological reasons not to just give alien invasives free rein to do what they want to do. Ecosystems include, for example, insect, bacterial, and fungal life, and these may be very poorly supported by alien plants, with whom they will not have evolved. The fact that some few species are able to make use of some alien plants is not a sound argument for saying that “everything is ok.” The abrupt changes wrought by invasive aliens is a threat to the sustainability of many of our ecosystems.

  16. Irrigation Systems brings up an interesting point; aren’t we humans part of nature and the local ecology? Maybe when we start perceiving ourselves as part of a whole we will start to understand things better and act accordingly.

  17. mr_brownthumb at plantsarethestrangestpeople recently did a two part post about this. It comes to the same conclusion more or less but is amusingly sarcastic!

  18. tamarix use more water, shelter fewer flycatchers and push out other vertibrates almost entirely. Not a great example.

  19. I fail to see the advantage in trading 50+ species of native woodland wildflowers for Garlic Mustard, or beautiful stands of wetland milkweeds, hibiscus, cardinal flower, etc., for Purple Loosestrife.

    Dames Rocket: folks just WON’T listen. I just returned from NW Illinois…it’s almost everywhere in every shaded stand and even sunny spots. Another plague… It’s like trading an intensely colored painting by Rembrandt for a canvas simply splashed by a bucket of paint; all texture, all detail, all diversity gone…

  20. I’ve just posted on my blog about Dame’s Rocket – – and half an hour later found this! The gist of my post is that there may be large patches of Dame’s Rocket but the research shows that it you take it out it makes no difference. And why does it and garlic mustard etc move in? Cos the deer don’t eat them but they eat most natives – and there are too many deer.

  21. My local neighborhood is buried under english ivy. It covers and kills natives and non-natives, and even pulls down whole trees without giving room for grasses to grow. That’s an invasive species.

    Some are just nuisances, like scotch broom, which sprout up and jump fires where the natives would not provide good fuel.

    Others, like many herbs – we’ve found nearly every herb that can grow here, is here wild, even if not at all native, are eaten by local wildlife, and don’t outcompete.

    We have done half our garden by pulling out plants judiciously; forming beds of natives and clearing out areas for plantings. It’s all about balance.

    Some invasive species should seriously be criminal to sell – here in central coast california several houseplants choke the local rivers.

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