Q: I have an obnoxious, unkillable, unpreventable WEED in my lawn. It is low growing and the leaves look a little bit like parsley. In summer it has almost-invisible stickers that make going barefoot impossible. I never had this weed until three years ago. HELP!
A: I feel sure you have lawn burweed. Spread isoxaben (Green Light Portrait) in September to prevent the seed from germinating.
If you can see the green plants, spray them with triclopyr (Ortho Weed B Gon Chickweed, Clover and Oxalis Killer).
Be sure to read the pesticide label for full directions.