roundup, applied repeatedly, is probably your only hope. handpulling is simply exercise for your hands, but will not eradicate this monster.

Can I use roundup safely around perennials? Considering the "open" nature of this plant, if I spray one, even assuming I can shield the nearby plants with a piece of cardboard or something, a lot of the poison spray will go on the soil and then may wash into the roots of nearby good plants.

Use a throwaway paintbrush--or one you keep only for herbicides. Dip it into the chemical and paint the leaves. But really, that method is best for persistent woody weeds like poison ivy or bittersweet. With yellow sorrel, it's grit your teeth and pull, pull, pull. If you are consistent, you can get rid of most of it.

If it's breaking off, your soil is fairly hard. It doesn't have a deep root system, and is fairly easy to pull. It should come up by the handful from the roots.

Ortho has a product out with Tricopyr ( which is used in the control of Oxalis and Yellow Clover. If used with a surfactant
(sold in Nurseries ) (locals use Dawn dish soap) to get product to adhere to plants.. est time to spray is 2 Days after cutting lawn with no rain expected in 24 hours. 4 oz of surfactant per gallon of product made.

Yeah, this Yellow Woodsorrel is hell as far as spreading like CRAZY, I've 2 different weeds doing exact same, it almost seems like they're in this together, which is the yellow wood sorrel and the spotted spurge which has little purple spots on them.. I'm about to use the post-emergence CELSIUS WG HERBICIDE, which, if can get rid of Virginia Buttonweed, hope that you NEVER GET THIS STUBBORN, VERY FREAKING HARD AND I MEAN HARD TO GET WEED EVER TO GET RID OF. I FORGOT TO GET THE SURFACANT STUFF THAT MAKES THE CELSIUS WG STICK TO IT AFTER SPRAYING THE CELSIUS WG ON IT SINCE ITS, THE BUTTONWEED HAS A SLIPPERY TYPE LEAF AND SO IT NEEDS THAT STUFF TO MAKE IT STICK TO THE BUTTONWEED, ELSE IT'LL JUST SLIDE OFF OF THIS STUBBORN, SO HARD TO GET WEED...OMG, BUT THE SORREL WILL SPREAD SO FAST, THEY SHOOT THEIR SEEDS OVER 3 FEET IN THE AIR. BE READY TO SPRAY EARLY FALL OR SPRING IN ORDER TO GET RID OF THEIR SEEDS THAT THEY RELEASED ALREADY THAT WILL BLOOM OR BE HERE NEXT SPRING.. I'M SPRAYING EARLY, EARLY SPRING, I MEANT WINTER IN ORDER TO GET RID OF THEIR SEEDS SO THEY DON'T COME THIS COMING SPRING...😁😁GOOD LUCK TOO YOU.I KNOW THAT I NEED IT..OMG

The only way to assure that the tiny Oxalis root nutlets don't regrow is to scoop out all the soil with the plant, which is a lot of work. Rugelar scuffling of the soil will eventually kill all the regrowable bits. Oxalis is annoying but at least it doesn't damage the plants it grows next to. It boggles my mind how many Oxalis, Portulacca and Prostrate Spurge seeds are in the soil bank and apparantly everywhere else. There are a couple native yellow flowering woodsorrels with red throats that I wouldn't mind growing.