I tested 6 products against oxalis. Under my conditions (moist soil, temps about 80) T-zone was most effective. Surge, Speedzone, and Quicksilver were almost as effective. A three-way and Drive were less effective. All spray solutions contained a surfactant. I used hand sprayers or squirt bottles( the bottles delivered 1/40 of an ounce per squirt). I tried to use label rates but the rates are approximate of course. The photographs are below, although the results are difficult to see against the grassy background. It appears that T-zone killed many of the leaves immediately and outright, and the seed pods turned brown also.