TheGardenLady received this comment from Susan:
My mother planted [Snow on the Mountain] 37 years ago. We bought her house 21 years and we are still trying to get rid of it. I am at my wits end!! But I have decided this year is gonna be the end of it! I have made it my personal challenge to finally see the end of it. I curse my mother every year when I see it. She thinks it’s funny. I however do not!! I cringe every time I’m in a garden center and see them selling it. It gives me anxiety. It must die!! Lol
It is interesting to this Garden Lady that so many of the plants that were brought to the US as ornamental or medicinal plants, have now
become invasive, noxious weeds. My lawn problem is ground ivy, glechoma hederacea, which was brought to the US as an ornamental or medicinal plant in the 1800s. It is interesting to me that it seemed to take so long for these plants to become pests. There is a long list of ornamental plants that have become invasive. Ornamental plants like Japanese and Chinese Wisteria wisteria floribunda and W sinensis, Callery Pear pyrus calleryana and Common periwinkle, Vinca minor are a few plants that have become invasive. Go here for some other invasive plants.
Your problem is Snow on the Mountain also called Goutweed or Bishop’s weed- Aegopodium podagraria. You are correct that this plant is difficult to eradicate. One has to get rid of all the root. To do it without chemicals, first remove your good plants from the area where you want to get rid of the Snow on the Mountain. Dig down 2 1/2 feet to get all the root. Put removed roots in the garbage, do not compost it. Then cover the dug area with black plastic and let sit fallow for 6 months. This should get rid of at least one area of the plant. See here.
You can visit your local Master Gardener to see what they recommend doing. If you are willing to use chemicals, ask which systemic they feel would be best to use. The US government has some recommendations.
Be persistent. Do not give up. Someone wrote that it took 12 years but finally the snow on the mountain was eradicated to a level where the gardener could keep it under control.
And don’t be too hard on your mother. It is a pretty plant. As you said, nurseries still are selling the noxious plant. I would be harder on any nursery that still sells the stuff. In your mother’s day, they did not know how invasive Snow on the Mountain could be. Today, nurseries should be more responsible. Let the nursery know that you would not buy plants from a nursery that sells invasive plants and that you will tell your friends not to shop there, too. Anyone who sells plants should have some knowledge of the plants they are selling and they would be doing a service to customers if they posted a list of invasive plants that should no longer be planted.
Good luck. And have a good laugh with your mother as she helps you get rid of the plant.