Not too long ago I used Roundup on some poison ivy and then also on
some liriope I was tired of digging up. It's always done great with poison ivy and I was thrilled to see that it also did a number on the liriope. (I've also given away a SLEW of liriope. I hate to kill things if someone else can use it.) I ran out of Roundup so went to buy more and see there are several other brands that will kill poison ivy and some were a good bit less expensive. Will they all also kill the liriope? And what's the reason for the price difference? Just advertising or something important?