I have applied Drive XLR8 4 times over the last couple of months on the same crabgrass. It seems to stunt its growth but it sure isn't killing it. I use the recommended label rate and sticker. I make sure it's been at least two days since mowing and wait at least 3 days before mowing. Irrigation is controlled to prevent washing it off the first day or so and then normal irrigation resumes. I even mixed a tracker last time to make sure I was hitting it good. Anybody else had this problem? Is there some kind of bad crabgrass in S. Florida that resists this stuff?