My lawn seems to have some patches of what I think is Black Medic. There were a couple of 2' x 2' spots where it was growing heavily and it choked the grass out. These areas of black medic ripped up quite easily, like a carpet (BTW, not a grub problem). I have had good results just tilling the soil in these places and reseeding with new grass.

My problem is I discovered a few more areas in back where the weed is not so dense. It's spread out over a 6' square area of lawn as small, separate sprigs. This makes it impossible to pull up as one, so I'll have to take other measures. I have read that keeping the grass tall 3.5" or 4" helps. I have already used two application of Weed-B-Gone (over the entire lawn) since April and it has worked well for the dandelions and white clover, but doesn't seem to stop this nasty variety of clover. I'm thinking of trying a spray application of Trimec Classic but I'm concerned about too many applications of herbicide. There is a link to a high resolution photo below. Any suggestions/advice? Thanks!

http://galleries.cigarweekly.com/Cloud9Bob/PotPourri/IMGP2594?full=1