Q: I have an aggressive weed in my lawn that I believe is yellow flowering wood sorrel. Can you suggest what I can use to kill the weed without harming my fescue?
A: Yellow woodsorrel, sometimes called yellow clover, is tough to control. It arises from a taproot each year and scatters copious seeds during its blooming season. In fescue you could use products containing triclopyr (Bonide Chickweed, Clover & Oxalis Killer, Weed B Gon Chickweed, Clover and Oxalis Killer, etc). These can not be used on bermuda or centipede lawns. A non-chemical option is to nurture the fescue precisely to get dense growth that chokes out the woodsorrel.