A "friend" planted some thyme, the herb, in a planter box next to my yard. It has now spread, in clumps, all over my 1 acre of property! The only thing that I can find to kill it is the killer spray that kills EVERYTHING, including the grass. Then I have a chick weed that fills in the patches that used to be lush, grees grass. I don't know how it is spreading so far away from the original plantings and how can I get rid of it once and for all? I thought it was all gone, at one point, and a week later, it was back! HELP! This has been going on for 10 years now. Even Bordines doesn't know what to do.