I have a 125ft by 30ft area covered in liriope. I only see the mounding variety. I cut it down to the dirt with a commercial mower and was going to spray it, cover it with weed barrier and then mulch an pray it didnt come thru but decided against that. So i rented a bobcat and a commercial tiller. i got all the mounds out and where new ones where coming up i just tilled down about 8 inches through out the whole area. Do you think if i rake out what i can and then put the barrier down and then mulch I am safe.