Wildflower Species to Compete with Invasive Grasses - Ask Extension
I’m a service provider in the Lake Champlain Basin and I am looking to assist a landowner in South Hero, Vermont. They spread wildflower seed a few ...
Knowledgebase
Wildflower Species to Compete with Invasive Grasses #931719
Asked May 14, 2026, 3:36 PM EDT
I’m a service provider in the Lake Champlain Basin and I am looking to assist a landowner in South Hero, Vermont. They spread wildflower seed a few years ago, and for the first two years it created a beautiful meadow. Since then, the wildflowers have struggled to return as the area has been overtaken by invasive grasses and weeds such as thistle, burdock, and chicory. They are wondering what wildflower species might be able to coexist with or outcompete these plants. Some of the area is also located over a septic mound. Looking for suggestions! They are enthusiastic about creating pollinator habitat.
Grand Isle County Vermont
Expert Response
Thank you for reaching out to the UVM Extension Master Gardener Helpline with your question, Molly.
It's so good of you to help this homeowner in South Hero -- the photo shows such a lovely wildflower meadow!
Alas: "invasives" live up to their name -- they procreate vigorously & push out native plants.
A great site for tackling invasive plants found locally is "Vermont Invasives":
https://www.vtinvasives.org/gallery-of-land-invasives
I offer the link above for your future reference and in case there are other invasives battling for resources in this wildflower meadow. It turns out that burdock, thistle and chicory are not official Vermont Invasives (yet). But they are all considered invasive weeds in parts of the country.
There are several options here, so the first place to start is identification. There are different species of burdock, thistle and chicory; so you might use Go Botany (a New England resource) to help identify the aggressive invaders.
Here are some links on Go Botany:
Common Thistle: https://gobotany.nativeplanttrust.org/species/cirsium/vulgare/
Burdocks: https://gobotany.nativeplanttrust.org/search/?q=burdock
Chicory: https://gobotany.nativeplanttrust.org/species/cichorium/intybus/
You can also look at the photos at these two "common weeds in Vermont" sites: [Just photos for identification -- no further info]
Depending upon how large the meadow is....and how advanced the invasion has grown, it's possible to battle biennials at this time of the year. They usually get a headstart and display prominent rosettes: one can take a spade and cut through the tap root at this time of year. For all of these weeds: you want to avoid letting them go to seed further, so for any that approach flowering: you can cut them down before they go to seed. Be sure to wear gloves and cover up legs & arms before going into battle, some weeds (like Wild Parsnip) contain nasty photochemicals that can blister your skin.
Finally: if the meadow is too large to battle by hand, then you can go back to the beginning: clear the meadow and start over. Alas: rototilling is likely to chop up taproots that will regrow....so solarizing (cut the meadow, cover with a black tarp and let the sun bake the plants for at least one season.....) might provide a better start for a new meadow of wildflowers. This is a lot of work unless the homeowner is able to catch the invasives early. I've had success with Wild Parsley (also a biennial with a taproot) using the "chop the taproot" method where I live -- but it took a few years of persistence each spring. Fortunately: seeing that you are winning the battle via fewer & fewer offenders each season can keep one inspired.
To offer some ideas for native plants that might do better, here is a link to "Gardening with Climate Smart Native Plants in the Northeast":
https://www.uvm.edu/d10-files/documents/2024-10/Regional_Invasive_Species_Climate_Change_Management_Challenge-1.pdf
Finally, for the septic tank site challenge, here's a link to a great resource from the University of Minnesota Master Gardeners (they have climate zones similar to ours):
https://www.uvm.edu/d10-files/documents/2024-10/Best_Plants_for_30_Tough_Sites_UMN.pdf
On page 30 of this "Best Plants for 30 Tough Sites" guide, you'll find a page dedicated to plants suited to growing over septic tanks.
I hope you find some resources that will be of help here, Molly.
All the best,
- Robilee
It's so good of you to help this homeowner in South Hero -- the photo shows such a lovely wildflower meadow!
Alas: "invasives" live up to their name -- they procreate vigorously & push out native plants.
A great site for tackling invasive plants found locally is "Vermont Invasives":
https://www.vtinvasives.org/gallery-of-land-invasives
I offer the link above for your future reference and in case there are other invasives battling for resources in this wildflower meadow. It turns out that burdock, thistle and chicory are not official Vermont Invasives (yet). But they are all considered invasive weeds in parts of the country.
There are several options here, so the first place to start is identification. There are different species of burdock, thistle and chicory; so you might use Go Botany (a New England resource) to help identify the aggressive invaders.
Here are some links on Go Botany:
Common Thistle: https://gobotany.nativeplanttrust.org/species/cirsium/vulgare/
Burdocks: https://gobotany.nativeplanttrust.org/search/?q=burdock
Chicory: https://gobotany.nativeplanttrust.org/species/cichorium/intybus/
You can also look at the photos at these two "common weeds in Vermont" sites: [Just photos for identification -- no further info]
- Vermont Wildflower Farm link: https://www.vermontwildflowerfarm.com/pages/weed-identification-photo-gallery?_pos=1&_psq=weed+identi&_ss=e&_v=1.0
- Common Pasture Weeds in VT link: https://efotg.sc.egov.usda.gov/references/public/VT/Common_Pasture_Weeds_and_Grasses_Vermont.pdf
Depending upon how large the meadow is....and how advanced the invasion has grown, it's possible to battle biennials at this time of the year. They usually get a headstart and display prominent rosettes: one can take a spade and cut through the tap root at this time of year. For all of these weeds: you want to avoid letting them go to seed further, so for any that approach flowering: you can cut them down before they go to seed. Be sure to wear gloves and cover up legs & arms before going into battle, some weeds (like Wild Parsnip) contain nasty photochemicals that can blister your skin.
Finally: if the meadow is too large to battle by hand, then you can go back to the beginning: clear the meadow and start over. Alas: rototilling is likely to chop up taproots that will regrow....so solarizing (cut the meadow, cover with a black tarp and let the sun bake the plants for at least one season.....) might provide a better start for a new meadow of wildflowers. This is a lot of work unless the homeowner is able to catch the invasives early. I've had success with Wild Parsley (also a biennial with a taproot) using the "chop the taproot" method where I live -- but it took a few years of persistence each spring. Fortunately: seeing that you are winning the battle via fewer & fewer offenders each season can keep one inspired.
To offer some ideas for native plants that might do better, here is a link to "Gardening with Climate Smart Native Plants in the Northeast":
https://www.uvm.edu/d10-files/documents/2024-10/Regional_Invasive_Species_Climate_Change_Management_Challenge-1.pdf
Finally, for the septic tank site challenge, here's a link to a great resource from the University of Minnesota Master Gardeners (they have climate zones similar to ours):
https://www.uvm.edu/d10-files/documents/2024-10/Best_Plants_for_30_Tough_Sites_UMN.pdf
On page 30 of this "Best Plants for 30 Tough Sites" guide, you'll find a page dedicated to plants suited to growing over septic tanks.
I hope you find some resources that will be of help here, Molly.
All the best,
- Robilee
