Monday, May 23rd, 2011...12:00 am
How to Deal with Snow on the Mountain
Aegopodium podograria #1 by J.G. in S.F.
TheGardenLady received this question from Janet.
I was given some hostas and there were some pieces of Snow on the Mountain mingled with them, which is taking over everything. How can I kill the snow without killing the rest of my plants? I have dug until I’m blue in the face.
There are quite a number of plants that were brought to this country because they looked pretty and horticulturists or gardeners wanted to plant them in their gardens in America or wherever they moved; then these plants became invasive. Unfortunately Snow on the Mountain, ‘Aegopodium podagraria Variegatum’, also known as Bishop Weed or Goutweed is one of them.
One nursery touts it as the number one seller for a ground cover. So it is still being sold. It is advertised to use for difficult sites. Many people say they love the plant and it isn’t invasive for them. However, some people rue the day that this plant entered their yard. One lady said when she sold her house she didn’t tell the new owners all they were getting. The government lists this plant as an AGGRESSIVE invasive (see here).
People who buy plants should check the invasive plant list before buying plants or buyer beware. Even nurseries don’t seem to keep on top of the invasive plant list, so they might not be aware of the problem. Always check pots when buying plants to be sure that you are not getting an unwanted guest, whether weed, disease or pest. But you seemed to have the misfortune of inheriting it when you got your hosta plants from a friend.
TheGardenLady thinks that you are doing the right thing by digging up the Snow in the Mountain. It is an uphill battle but gardening is not easy. And I think of the work as being cheaper than joining a gym.
It is best to try to get the plant out in early spring when it is just coming out. If you miss all the plants and the plant flowers, to prevent more plants by its self seeding you should remove the white flower heads before they set seed.
A friend with one of the lovliest and weed-free gardens swears by a tool called a Swoe that is a British garden tool invention. Her sister said that it is tricky to use; but my friend disagreed saying that it is the easiest tool she ever found that is effective and easy for getting rid of weeds. It seems to just cut the weeds off at the ground level, but doing this enough times will prevent the weed from growing. The tool is not cheap- and the USA Amazon.com, the cheapest place I can find it, says it is sold out; but Amazon UK talks about it (see here).
Another thing you can do is, after pulling or cutting down the Snow on the Mountain plant, try covering the area around the hostas with mulch or black plastic to try to kill the unwanted plants.
As a last resort, without using chemicals (see here), you could re-dig all the hostas with the accompanying Snow on the Mountain plants. Clean off all the soil around the hostas. Remove all the soil with any Snow on the Mountain plants or their roots. Hostas are a really resilient plant and this won’t hurt them. Bag everything you don’t want in black trash bags, including the soil. Then let the closed bags sit in the sun for a week or so to allow everything to bake in the bags. Do not compost this. Refill the area where you dug the plants with new topsoil- I would buy bags of it because you know there are no weeds or pests in the store-bought bags of soil. Replant the hostas. Watch the area carefully in case any seeds of the Snow on the Mountain plants took root or some of the root remained. Yank out the unwanted plants early so they can not spread.
I would not plant anything besides the hostas in the area until I was sure that I had removed all the Snow on the Mountain. The hostas should grow back beautifully- and if you bought some of the new soil with slow release fertilizer, I feel certain that your hostas will be the sensation on your block.
If you want to use a chemical, there is only one that seems to work (though some people say that it is not effective in eradicating Snow on the Mountain.) But this chemical can kill other plants like your hostas. So this product has to be used judiciously. The chemical is glyphosate and the brand names are Round-up, Rodeo or Pondmaster.
It is advised by the North Dakota extension office that you brush or paint the product on the leaves and hope that it will kill the roots. Whenever you use a chemical, READ the LABEL carefully and follow the directions. To me it seems like it would be easier to dig up the hostas and replant them. Also, I dislike using chemicals in the garden and glyphosate is being banned in Europe.
These methods can be used on other invasive plants. Please read the link to the USDA information on eradicating Snow on the Mountain or before buying any plant to check to see if the plant you want is now on the invasive plant list.