Invasives and Other Garden Regrets

New gardeners beware! One of the worst rookie mistakes we can make is to introduce invasive plants into our gardens. I ignored a lot of good advice when I started out, but honestly, no one warned me about these plants. With the emphasis on the benefits of local growing and shopping, I think we’re a little more savvy now. Or I hope so.

If you only study one thing before you start, find a reliable source in your area that lists known invasive and banned plants. You cannot rely on garden nurseries or neighbours to advise you on these things: sometimes they don’t know or don’t care. But believe me, if you end up with something in your garden that takes over your growing space, you will regret it forevermore. Some aggressive plants are just impossible to get rid of.

Invasives vary by region: what’s native in one area, does not have the checks and balances of it’s natural eco-system in another area. I’ll show you my plant regrets at my old zone 5 (Ontario) garden so you can get an idea of how serious this can be. Read my tales of woe and take heed!

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The Invasives I Unknowingly Introduced

Mint (peppermint) – This was the first free plant that I was given by another gardener when I was just getting started. In hindsight, it’s not a gift at all but a test I failed by simply ever planting it. That one mint plant became a swath of relentless growth, spreading by roots, undaunted by even the hardest clay soil. Today I still grow mint but only pots where I can contain it.

Lemon balm – I love the smell, especially when the lawn mower catches it and the air fills with that sweet lemon scent, but this eager grower also took over a huge area of my old garden and no amount of pulling, digging, or smothering could get rid of it. Today, if I want to smell lemon, I’ll get a lemon.

Obedient Plant-Design wise, I love this plant. It’s one good looking plant. Like a rigid, compact foxglove with good posture. But wow, once this plant started spreading, it was choking out my Asiatic lilies and everything else it could get near. One summer I thought I had pulled it all out, and more plants returned. I swear I could hear the roots creeping through the soil as I slept.

Donkey Tails (Euphorbia): In some zones they are considered horridly invasive. In my garden, they became insanely dominant because I wasn’t careful to lop their heads off before they’d go to seed and spread by wind to the neighbor’s garden. I liked them for a while but everything loses its appeal when it grows too easily.  Gardening is like a great game: there has to be that perfect level of challenge to remain engaged.

Musk/prairie mallow I had the kind that is a most annoying pinky/light purple colour. It’s not pretty and it self-seeds everywhere. Enough already! And to make matters worse, it’s easy to mistaken for hollyhocks when it’s just sprouting up so often you don’t know to pull it out until it’s rather tall. The hollyhocks are welcome, the mallow: not!

Goutweed. There are no words for how frustrating it is. I think you’d have to excavate all of its soil with a Bobcat digger to begin to get rid of it. And then nuke it. Twice. Of all the invasives, this one is my worst nightmare.

Volunteer Invasive

Garlic mustard – Some years ago garlic mustard suddenly had a stellar growing season. It was EVERYWHERE. In every garden, every walkway, every lawn, along the paths in the woods. Evidently, growing conditions were perfect and it just flourished. I spent hours and hours pulling volunteer mustard seedlings out of my garden. After about 3 years, it was no longer a problem.

Each year’s growing conditions favour some plants and make others struggles but the Year Of The Garlic Mustard was the most epic one I can recall.

Landscape Fabric

A Short-term Solution That Creates More Work In The Long Run
It sounded too good to be true, and for me, it was. One year I set down a lot of landscape fabric under my garden rocks. And it did keep the weeds down for about a year. And then I realized the weeds were simply forming monster roots under the fabric and when they finally did poke through, they came up with a vengeance: all tangled up in the fabric no less, so everything had to be yanked out which was far more work than simply weeding. When it comes to weeds, there is no free lunch.

Double Digging

Double digging is often recommended in garden books and magazines as a means for dealing with clay soil. In my experience, it’s a complete waste of time and energy. I couldn’t begin to make my clay garden flourish until I added many inches of good compost and loose (not clay) soil on top of the hard clay. All the double digging ever achieved was to temporarily break the clay apart. Time and rain would cause it to meld back together again. It did, however, end up providing a good base for better soil on top.

Feel free to add your problem plants in the comments.



  1. says

    I think double digging is only good for waking up all those dormant weed seeds! I only once did it, and I had more weeds than I could shake a stick at.
    I totally agree on the gout weed, obedient plant, mint, and lemon balm. I have to add oregano to the list, it took over one herb garden I had at another house. I don’t grow it now because I don’t care for fresh oregano in cooking. And lily of the valley and periwinkle are very invasive!
    I actually like the mallow, it doesn’t go too crazy on our property, a little one here & there but not unmanageable.
    Debbie :)

    • says

      Happy New Year, Debbie,

      You just gave me flashbacks: periwinkle and lily of the valley were both problems at my old garden. I was given my mallow by someone who really loved it. It’s almost forgiveable when the intentions are good! 😉

  2. says

    I agree that double digging is not worth it. Also I would only plant mint in a container. I would never encourage anyone to plant bishopsweed, but I have found it manageable in dry shade.

    • says

      I too have wasted time and muscle aches double digging. I am so happy with my “lasagna” gardens that I doubt I will go back. One garden regret that I have only learned through repeated lessons is not to plant a small bush, small tree, or vine without proper support or landscaping. I have had many plants accidentally mown down. What looks like a plant to me can look like a weed to my husband or the kid who occasionally mows my lawn. I need to make my organization (or lack of) a little more obvious and purposeful. I often bite off more than I can chew, which doesn’t help.

      • says

        I think anyone who really loves gardening always takes on more than they can manage! I’ve also mowed and pulled a few valuable plants in error over the years.

  3. says

    I’ve found the exact same solution with hard clay–this isn’t soil, it’s subsoil left after the developer stripped it. The greatest gardener on earth couldn’t make it grow roses, so…topsoil and mulch, all the way! (It gets moist and loosens a little once well-mulched, probably owing to happy worms taking the occasional wiggle through it. It’s still not great, though.)

    • says

      You reminded how I could not get my shovel through the clay soil but the worms could manage it somehow. I guess it’s much like weeds getting through asphalt: all in good time.

  4. says

    Evil #1: English Ivy, #2: Periwinkle, #3: LEMON BALM, #4: Herb Robert, #5: an unknown invasive, low-growing plant, with delicate pale blue flowers which covers EVERYTHING. Gah. I think it was imported from England by the previous owners.

  5. Carrie says

    Lily of the valley and carraganas. Our house was built in 1962 and we bought it March of 2013. Under all the snow (about 4 feet) in the backyard I found lily of the freaking valley. Come summer I started digging: it’s poisonous to small animals. It had roots under the cement freaking walkway 3 feet away! I dug out a root ball as big as a cabbage and I’m sure there’s still more.
    As for the carraganas… Who plants carraganas 3 feet in from the property line and allllll the way around? The seeds were pinging off my windows and the branches were scratching my house. I tried to trim them back and it turns out a bunch of them are rotting from the inside out. There is no way to get rid of them. Fire makes them happy, the roots of a 1 meter by meter plant are the size of a large pickup truck, clipped branches left lying root crazy fast and when the pods snap open the seeds get flung meters in every direction. We’ve decided to try just taking a chainsaw to them, as low to the ground as we can. Every time we see new growth, we cut it off as traumatically as we can. Hopefully that will kill them and in about 20 years the roots will loosen enough to float up. The next owners can deal with that problem.

  6. Jeanne Romero says

    Morning Glory from hell. Our neighbors planted a morning glory and it took over our backyard in one season! It crept into the house, even! Thank God we had a really long and unusually cold winter and it managed to kill most of the creature off. Never, ever, ever plant Morning Glory in south Louisiana! The same goes for wisteria. You can actually see that stuff growing.

      • Rhonda says

        I’ve been battling Wisteria for over 27 years! It went unchecked for 10 years before we bought the house. I think I’m finally winning!!!

      • says

        OMG, My neighbor on my left had wild morning glory that I fought for 14 years. Then the ones on the other side planted flowering bamboo ( can you believe it) Yes both tried their best to take over my yard. The only way I finally took care of both was I moved. Haha I feel sorry for anyone that has to deal with uncaring neighbors and their very invasive plants. Portland Oregon Bob

  7. Renee says

    Mint was my lesson. I knew it was “invasive” but I didn’t really understand what that meant. I thought I could plant it in a corner and control it – ha! I had a good crop of strawberries going but am having to tear them up to get to the mint roots. Not sure if attempting to till it up would just cause it to spread more?? It’s a tangled mess of mint, strawberries and crab grass. Ugh. And good to know about the lemon balm. Same family as mint, correct? I am getting ready to start some this year for tea and medicinal purposes, but I know now to use a container for it.

    We have clay soil as well, we live in the heart of “pottery country” for a reason. It’s taken me 4 years to have somewhat of a decent foundation for growing. I have used a combination of topsoil to loosen it up, compost, and manure. We have our own chickens and our tenant’s daughter has horses so that’s what I used. Keeping my fingers crossed that the horse manure doesn’t totally ruin it thanks to that herbicide chemical that I have since learned about.

  8. Judy Cain says

    Coreopsis is my nightmare. It was given to me by a gardening “friend” and eventually took over a whole terraced garden. I still did it out as soon as I see the little green fiends peeping out of the soil. Funny, though, when I tried to plant it in an area I wouldn’t mind having it in . . . no way.

  9. CJ says

    I believe Wild Morning Glory is a scourge on the earth. It spreads by a massive root system which goes several feet deep. You can pull and weed until your hands are worn out and never get all the roots. If you choose to use weed killer, it still takes several years to kill it off. It’s the Utah version of kudzu *grrrr*

  10. Heather Letalien Costa says

    I used sand/compost to mix with my clay soil. So far it has worked fabulously. I have a garden that is overcome with Lilies!!!

    • says

      I think it depends entirely on how much clay is present. In my previous garden, it was all clay. Amending it would have been futile. Other soils with clay but also loam still having a fighting chance!

  11. JudeB says

    I don’t know whether you grow Acanthus spinosus in your country, but if ever it or ‘bears breeches’ are offered, run for the hills!! A KINDLY neighbour gave me a piece of it years ago when I was just starting to re-plant a garden that had been left to go to rack and ruin for years, and I still have the darn thing, in spite of digging it out year after year after year. I even tried burying it under an old carpet but gradually the carpet started to lift up in the air as if there was someone underneath it, a quick peek, and yep, you guessed it, the darned bears breeches was still growing madly. GRRRRRR!!!

    Judi in the UK

  12. Tati says

    How did you get rid of the gout weed? We bought a house where previous owners planted it…and didn’t contain it. We just want it gone because we are trying to make the yard our own. Any advice or helpful tips would be much appreciated!!!

  13. Linda says

    I’m in zone 10a, so things pretty much grow year round. My lesson learned is the beautiful and very prolific Mexican Petunia (Ruellia brittoniana) and definitely Mint when I lived up north in 7a.

    PS: I would really like to have a bit of clay to mix in with all this sand.

    PPS: The grass is always greener…
    where you water it. :)

  14. Cindy Reynolds says

    the ones I have the worst problem with is Vinca major (here when we moved here) and argeratum…I pull it out by the handfulls….that and Autumn Clematis….Morning glories yank out pretty easy….and I love my Gooseneck Loosestrife….but planted it in a place where it can go to town if it wants to….so far it stays pretty much where I planted it…

  15. Martha says

    My list of invasive plants includes silver lace vine, rose of Sharon,Virginia creeper, & trumpet vine. Love them all but a little goes a long way. Why can’t foxgloves & hydrangea be invasive?

  16. Beverly says

    Yellow archangel! Can’t believe I paid for this nightmare. It creeps along and roots from the stem wherever it touches. It is now coming up between the patio and the house. It loves to climb into potted plants. It laughs at weed killer and begs for more. Digging it out seems to be the only-and endless-solution.

  17. Judy says

    Good reading. Thanks for passing on what not to plant, and some of you are truely amusing in your plant angst. Mine is Gooseneck Loostrife. I love the flowers, hate the plant. I try and look at the yearly clearing back as a cathartic exercise in ridding my life of unwanted, and intrusive things.

  18. Lynn G says

    I remember spending one summer years ago pulling out Chinese Lantern that had taken over the garden and was working its way into the driveway! Lady’s Mantle and self-seeding False Sunflower have become pushy in my new gardens in Ontario, along with Rose Campion, oregano and evening primrose. I can prune back Star of Bethlehem in shade only to find it grown again days later. Pretty but…..

  19. says

    There’s just one thing you can do with goutweed. Accept it as a vegetable. Getting rid of it takes years, maybe decades, maybe forever. I thought, I couldn’t trust my eyes when I saw it in a web shop once. Are there really people paying for it?
    My hated invasive is Goldenrod. Nobody cared much for the garden the past years and it’s almost everywhere now and killed a lot of other plants :(

  20. says

    Icelandic poppies! We planted a few one year. It took forever to get rid of all the poppies that started growing from the seeds. Great big taproots made them difficult to eradicate.
    Also – trumpet vine! That thing will send out roots and try to start other plants ten feet away – through the asphalt.

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