I tested four herbicides on clumps of clover on my neighbor's vacant lot. Low quality turf, which was non-irrigated. Weather mostly had daily highs of 88. The result: Surge..........Good T-Zone........Excellent Speedzone...Good Quicksilver....Poor There were a few clumps of violets in the area, but not in all plots. T-Zone was good on violets. What are your experiences on the more difficult weeds?