Round up will kill ANYTHING it touches...so the product specificing brushy plants is kinda like "overkill" for herbaceous plants like lirope. Round up application to leaves makes the plant "think" it can no longer take up water so it withers from dehydration. .You can find more info on the Scotts website.
Yes it will kill the Liriope, but it will also kill any grass or plants that you wish to keep in your yard as well. You can use a foam brush applicator and just paint the Liriope, but you won't be killing the rhizomes underneath the plant. You will probably need to repeat each time you see new ones pop up for the next couple of years.
I applied some Round up today with a foam brush to some of the liriope to see what would happen. Jeeez, so I have to KEEP applying it? This stuff used to fill my entire front yard (literally FILL the yard) so they'll pop up forever!! :-( I dug up the yard full a few years ago and planted shade grass, but it didn't last very long. Then last fall I had the yard tilled and pulled out all of the liriope I could. Is there any other way to eliminate it but keep the yard usable for the other plants I've put in?
I'm afraid there's no easy answer, Louise. You'll just have to keep after it and eventually you will be rid of it.
I made the mistake of planting some of this, too! Eventually - I'm still waiting for eventually after 15+ years! Last year I resorted to BLEACH! Showing some success.
Had I known years ago this would never go away, I'd have re-thought the idea. Live and learn. :-)
Painted lots of the liriope with Roundup and a sponge brush about a week or more ago now and none of it is showing the slightest desire to dry up, turn brown, die, or whatever. Tomorrow I guess I'll go out and start digging up the extra little boogers. VERY resistant stuff, this liriope!
Try 1 gallon cider vinegar, 1/2 cup Dawn liquid and Epson salt ( which I left out because did not have any). This worked fie on a 3' thistle, dock. Only thing that needed a 2nd application was garlic. DO NOT get it on anything you want to grow.