Q.I Want To Kill Off Pokeberry Stumps, And Grapevine Stumps.
If I put a mixture of vinegar and Dawn on it, and cover it with black plastic will that work? The grapevine stumps are entwined in a large bush. The pokeberry is right next to a sidewalk.
Certified GKH Gardening Expert
'd be more inclined to use a bush killer herbicide as those two plants you mention are very stubborn. If you cut the grapevine about 4 inches above ground then use an herbicide, it should take care of it. Vinegar will not help. It may burn the top foliage but it won't kill the roots and it may kill nearby vegetation.
Or if you want to try the plastic, clear plastic works best during the hottest part of the year.
https://www.gardeningknowhow.com/garden-how-to/info/use-vinegar-in-gardens.htm