How To Get Rid Of Resilient Unwanted Ground Cover

Question From: Stewartstown, Pennsylvania, United States
Q: Hi Nancy, I do not know the ground cover type plant that is growing out of control in my garden. We planted a few that a friend gave us decades ago and now want to get rid of them. Have tried Round Up with no luck they keep coming back! I have taken a sample of this plant to Penn State Extension in York and they gave me the name Polygonum....I looked on the internet but none of those plants looks like mine. When I was given the little plants the lady called them "watermelon plants"....they do smell like a melon for sure. Can you help?

A: Lee, I am not familiar with the plant and cannot give you a silver bullet. My recommendations are labor intensive and time consuming :-( The idea is to weaken the plant and then hit it with a strong concentration of RoundUp and hit it again as soon as it returns. How you accomplish this depends on where it's growing. In a perennial bed you would have to weed it by hand and then Roundup the new growth. Watch it like a hawk and RoundUp the new growth again and again and again. You may have to apply the RoundUp with a paint brush. You must not let the plant go to seed. For large patches you might weed it out, Round Up the area and then cover it with black plastic for a season. Not pretty. Rototilling is a no no as it only breaks up the roots making things worse. Because there are probably seeds in the soil and they may remain viable to years, you must be vigilant so as not to allow it to re-establish. Good Luck. Best And Happy Yardening, Nancy.