Peter Del Tredici gets real about “wild urban plants”


IMG_0337 We last wrote about Peter Del Tredici's radically practical view of weeds wild urban plants here in Elizabeth's post and you get a hint of the controversy he's stirring up in Slate's report and his own piece in the Boston Globe.

And guess what – I got to hear Del Tredici in person (at ASLAhere's his hand-out.)  So I might have a response to Elizabeth's objection to his suggestion that we leave abandoned properties alone with their urban weeds.  Quoting her: "But it will take a lot of mindset changing to make vacant lots filled with the plants he’s talking about seem anything but blighted."

First, there are some super-practical reasons for following his advice – most cities don't have the money to remove all the invasive plants and keep them removed.  This "spontaneous vegetation" covering vacant lots requires absolutely no maintenance, and they're serving all sorts of ecological services (especially erosion control).  And these plants are there; they don't need to be bought and installed (after nuking the undesirable plants).

And sure, these urban meadows aren't gardens, but with the vines and woodies removed and an adjustment in our aesthetic judgments considering their location (NOT in our front yards) they're not so bad.  As an example of how our concept of good and bad plants is always in flux Del Tredici notes that the Central Park Guidebook of 1869 referred to “blessed dandelions”, and sure enough, dandelions are now starting to make a comeback.

And finally, we're talking about a whole lotta acreage here, with 40% of Detroit's land now abandoned – an area the size of Boston – and it can't ALL be turned into farms.

Del Tredici believes that this is the ecology of the future and the challenge is not how to eliminate these plants but how to manage them to better serve our needs.

Now readers, what do you think of this prime example of his philosophy of urban ecology?  They're photos of Landschaftspark in Germany, which Del Tredici cites as the country taking the lead in this approach. Apparently in Germany they view plants that grow spontaneously with no human intervention as natural, regardless of where the plants came from originally. "Germans aren't romantic about this, like we are." (Click here for lots more images of this abandoned industrial park.)  In the U.S., Connecticut College is doing research along these lines, and an inspiring book on the subject is William Robinson's Wild Garden.

Germany3flickraur2899I've gotta say this approach, right or wrong, is what I've used to replace my own back lawn.  Instead of buying plants to cover 1,000 square feet on a hillside (quickly, before the soil washes away) I used a vigorous Sedum that grows in my neighborhood as a weed – S. sarmentosum – and it filled in completely in just a couple of months.  It needs no mowing or watering, and it actually gets thick enough to block out weeds.  It's beautiful (as you can see in the photo below, with clover) and when it blooms it's swarming with pollinators.  What's not to love?  (Here's my report on creeping sedums as an alternative to lawn.)


I managed to get my hands on a copy of Wild Urban Plants of the Northeast, which is an actual field guide for weeds, and I can't wait to identify all my favorite and not-so-favorite ones.  As Del Tredici says, "You can't have a relatonship with a plant unless you know its name" and that sounds right to me.

Photo credits:  large photo of Landscraftpark, and small one.


  1. Great post, and an interesting topic – sometimes the most environmentally friendly thing to do is leave a place un-meddled with for awhile… And I think it serves us well to appreciate the messy, chaotic beauty in something we are not trying to control.

  2. Sounds good to me but in my limited experience working for City and State Parks Departments – I’ve never seen anyone have the budgets and manpower to manage an entire area. They always keep the human corridors tidy and let the space behind the tree line or hedgerow go wild.

    I have a lot of experience with invasives and noxious weeds and I don’t see a happy ending to that story. I don’t see a way we will ever put things back into order. I now wonder if anything was ever really in order to begin with.

  3. It’s exactly the same with front yard veggie gardens and other alternative approaches to space use. We need to make a conscious decision to see the beauty in gardens which aren’t the traditional green turf.

  4. It’s a moot point, since cities don’t have the money to exterminate and replace all of their invasive plants, anyway.

    And, once again, there seems to be little distinction made between non-natives and *invasive* non-natives. I’m sure that business owners won’t mind a bit of non-native clover growing in the lot next door, but they’ll sure as hell mind when kudzu grows there.

  5. Okay, I just finished reading the Boston Globe piece, and I have some bones to pick with. One, the author repeatedly states that spontanious plants are a food and shelter source for wildlife. Invasive species very often do not provide the appropriate type of food or shelter to native species. Specialized insects, for example, can’t survive at all without their particular native host plants. But invasive sparrows can nest anywhere, which makes those invasive species look at a glance like they are good habitat.

    And does anybody think it’s sane to leave plants growing on rooftops that haven’t been designed to hold them? That sounds like damaged buildings in the making.

  6. Sure, non-natives like sedums or clover are welcome, and apparently there are folks who adore pampas grass & scotch broom. But what about out-of-control weeds with thorns that easily pop a bicycle tire ?

    Yellow star thistle is horribly invasive here, and impossible to control. The flowers are innocuous enough & its pale green stems & foliage – even without rain for 3+ months – would have you thinking that it belongs here. But just try to walk through a field of it & come out without painful scratches & a few embedded thorns – can’t be done ! Let a vacant lot go untended for more than a year & sure as the sin, you’ll have star thistle there. Nobody in their right mind wants it on their land as it renders it useless, unless you want to raise goats, the only creatures interested in the stuff.

    Does he address issues with plants like these ? I mean, if it’s pretty or functional, obviously people are willing to overlook the native status or invasive possibilities. But what does he think about an entire region possibly overtaken by an obnoxious invader ?

  7. I have written on the subject and own seven species of weeds in my collection of one hundred.

    Only bright people with vision could embrace such a simple, intelligent approach to biodiversity.

  8. Love the industrial park. Read a thesis years ago to do similar thing with the old coal stripped mined areas of Appalachia. I spent time as a kid scrambling all over high walls and swimming in strip pits. (Don’t tell my mother). Very interesting places.

  9. What a fantastic topic while I live in an Urban Area but most ideals I would love to move to a more country setting this year we did our first garden a 16×10 traditional row garden. While our garden yielded mostly tomatoes and peppers I thought it would have been better if we got some of the cantaloupe we planted but tis next year

  10. A recent NYT article pointed out that Homo sapiens is an invasive species to every continent except Africa. I think we’ve seen how that has turned out.

  11. Peter loves stirring the pot with challenging and out of mainstream thought theory.
    That’s one of the reasons why he is so beloved by his students, former students and peers.
    While I support his theory in most part I can also grasp the ethology for some potential problems due to the crowding out and loss of native habitat that supports specific species that might perish because it no longer has the native host to exist upon.
    Should evolution of the strongest be upheld or could some selective editing be introduced so that we keep some modicum of balance?
    Keep it up Professor del Tredici. Your students love you.

  12. I haven’t read the Globe article yet, so this may have been addressed.
    Often abandoned or empty city lots have become repositories of trash, bottles, needles and condoms. In addition to some desirable or harmless wildlife, they can also be home to rats and unwanted racoons.

    Is the idea to clean them up and then let them go to seed? If the human touch or presence isn’t obvious (such as gardens and/or art) why will the attitude towards the empty lot change? And when the bottles and trash begin to accumlate, who is supposed to enter the native weedpatch to pick up and clean up.

    It seems like the idea igores how people behave towards something that no one “owns” or has an investment in.

    I hope experience proves me wrong, but I think a “wild” empty lot theory isn’t addressing the outcome of benign neglect.

  13. Humans are at what, 6 billion and counting? Despite the fact that we have dramatically altered most of the usable environments on the planet, some things get ignored or left untended. Let’s face it. Not everyone is a gardener, much less even notices the shrubberies around them. We are a busy species and have other things to consume.

    I read the Boston Globe article and it was a rehash of a similar one from a while back. Del Tredici really isn’t suggesting anything all that dramatic or alarming. This sums it up quite well.

    “In his book and lectures, Del Tredici proposes an approach to urban wild spaces that is less about planting and more about editing, in which plants are allowed to grow naturally and then only maintained minimally to weed out truly undesirable species, like vines that choke out other plants.”

    All he is suggesting is that if and when anyone should get around to tidying up the wild places in urban environments, make it easy on yourself, stretched budgets and the environment and utilize what wants to grow there as much as possible.

    Why is a low budget garden maintenance plan so earth shattering?

  14. What a load of garbage. While it is not necessary to plant all vacant lots to lawn, saying that it is okay to leave invasive species thrive in urban settings is just plain ignorant.

    Many invasive plants cause real problems, even in an urban setting. Ask folks in the UK about Japanese knotweed. They spend billions of dollars every year keeping it at bay. Its roots are so powerful that it breaks up blacktop parting lots and streets; even concrete sidewalks and building foundations. Many banks in Scotland will not write mortgages if this plant is present on the property.

    Giant hog weed and Wild parsnip will cause deep chemical burns that can take a month or more to heal, and can cause permanent scaring.

    My customers pay me thousands of dollars to cut out weed trees that have grown into their security fencing. These trees and shrubs provide cover, reducing security for the property. If left untreated, they will destroy the fence. The cost of new security fencing can run many thousands of dollars.

    I could go on, but if you haven’t been convinced by these couple of examples, no amounty of reason is likely to convince you.

  15. I am curious why Del Tredici thinks of vines as “undesirable”,just because they might choke out other plants; seems to me that a lot of plants choke out others by taking over their habitat (isn’t that one of the reasons invasives are disliked?). Maybe they just need “editing”.

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