Weeds

Eliminating Goutweed While Saving Your Other Plants

The green-leaf form of goutweed (Aegopodium podagraria). Photo: martiroz, depositphotos

By Larry Hodgson

Question: I have a serious problem. Green goutweed is invading my flower bed and that of my neighbor. We’ve been trying to get rid of it out for two years, but nothing we tried—pulling, digging, rototilling, herbicide, etc.—worked: it just keeps growing back! I’ve been told that laying wooden planks on the ground for a few years will get rid of it, but I have a lot of valuable plants in that garden. I’d be afraid to relocate them temporarily while waiting for the planks to do their job, as I don’t want my flower beds elsewhere to become contaminated by a rhizome from this horrible plant. What should I do?

Nancy Clarke

Answer: Yes, you do indeed have a serious problem. Goutweed (Aegopodium podagraria), also known as ground elder, bishop’s weed and snow-in-the-mountain, is an extremely invasive plant due to its dense growth and numerous rhizomes that produce dozens of satellite plants. It can choke out almost any plant in its path. And you don’t even have the more ornamental variegated variety (Aegopodium podagraria ‘Variegata’), with green and white foliage, which is a little less vigorous, but instead the original form, a true garden thug with entirely green leaves. It is certainly one of the most difficult weeds* to get rid of. 

*To give the devil his due, goutweed is also a medicinal and edible plant that some people appreciate… but usually not gardeners!

Goutweed rhizomes.
Even the smallest bit of goutweed rhizome will make a new plant. Photo: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Additionally, you’re wise to be concerned that plants salvaged from the infested bed might include a piece of goutweed rhizome that could go on to take over your garden. That happens readily, as its rhizomes easily mix into the root system of desirable plants and can start a new infestation. I have two suggestions in this regard.

The first is to abandon the mother plants when you cover the bed, killing them too. Instead, take stem cuttings. Surprisingly few gardeners realize that the majority of perennials, shrubs and other ornamental plants are as easily multiplied by cuttings as well as by division. And when you take a stem cutting, no unwanted rhizomes will follow. So, plants grown from stem cuttings will be free of goutweed.

The second option is to dig up the plants, wash the roots, extract any rhizomes you see, and then plant them up in pots (not in another flower bed) while you’re waiting for your treatment to be effective. That way, if goutweed were to appear in some pots but not others; at least you could replant the goutweed-free plants without fear of reintroducing your enemy.

A Tarp Rather Than Planks

Black tarpaulin covering the ground.
Covering the infested section with a black tarp rather than planks will be more effective in suppressing goutweed. Ill.: Claire Tourigny

The idea of covering your garden with planks is quite good. That way, you’ll cut off the light reaching the goutweed and without light, no green plant can survive, not even goutweed. A thick black tarp, on the other hand, would be more effective than planks, as some light can pass through the gaps in the planks and keep some goutweed plants alive. A light-excluding tarp will cover a larger area without letting any light whatsoever get through. You could use bricks, stones or planks to hold the tarp in place or hide it under mulch. 

Note that your neighbor also has to do the same thing at the same time as you; otherwise the plant will creep under the fence and come back to invade your garden in no time!

It takes at least a full growing season without light to kill goutweed. Established plants will likely need two years. Sometimes, a very weakened stem or two will even sprout after the colony has been without light for two years, a sort of horticultural last gasp, but if you cut it back promptly, it won’t have the energy to regrow and that will totally eliminate the goutweed. So, if you apply this technique in the spring (2022), the flower bed probably will be free of goutweed and ready to replant in the spring 2024. 

Garden writer and blogger, author of more than 60 gardening books, the laidback gardener, Larry Hodgson, lives and gardens in Quebec City, Canada. The Laidback Gardener blog offers more than 2,500 articles to passionate home gardeners, always with the goal of demystifying gardening and making it easier for even novice gardeners. If you have a gardening question, enter it in Search: the answer is probably already there!

8 comments on “Eliminating Goutweed While Saving Your Other Plants

  1. marianwhit

    I used the tarp method and left it in place two years. Every year (now 15 years later) bits of it sprout, and I carefully dig it out with as much root as possible and put it in the sun to fry. Be prepared for a protracted battle, and please don’t plant it (no matter what anyone says).

  2. Hi Larry,
    Goutweed is definitely the most horrid, tenacious weed I have ever encountered. I have an acre of land and it has, over four years, spread through 6 gardens (some veg, some flowers,) AND across two lawns. IT is crazy-making trying to get rid of it and I don;t have the time/energy to dig up entire gardens to get rid of it (Let alone the lawn). I tried the heavy black plastic on some areas but it just came back more vigorously in areas adjacent to the plastic. I cannot cover my entire property in plastic.
    SO NOW I am trying to find species (and indigenous ones preferably) that will compete with it and maybe win the battle for me. Do you know of any ground covers or other plants that can complete successfully with goutweed? Thanks for any feedback. Brooke (Kootenays of BC)

  3. Carol Gray

    We have a similar problem with anemone which our landscaper thought would be a good idea to plant in our perennial garden around our pool (!?). For 2 years we have been pulling it up and in the process we have lost many other beautiful perennials including small flowering shrubs. The rhizomes are 18 -24 inches underground and they clump and cling around the root system of other plants, making it almost impossible to remove without killing the desirable plant. I hate to look at an ugly black tarp around our pool for a full season but it that’s what it takes, I guess I have no other choice.

    • marianwhit

      Which anemone? There are many, some N. American native, and others not. Just curious!

    • Maux Woodrow

      We had an extensive gout weed problem with our yard and our neighbours. We have a large maple tree which only gout weed seemed to be able to grow around. We started by digging out as much of the gout weed as we could. We then covered the area with cardboard and newspaper to form a thck layer. We then covered this with more soil and another layer of newspaper. Finally added mulch on top and left it unplanted for the year. The second year we were able to successfully plant a shade garden and have had very little weed come back. We did use old shingles under the fence between our yard and our neighbors and covered this with mulch. Fortunately, they mulched on their side as well. It has been 3 years since we did this and so far very little comes back.

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