How long does it take to die and how often should I spray it? I've sprayed some crabgrass in my yard and its dying slowly. I've sprayed it for a second time about 1 week after my initial spraying. I used WeedStop from Spectracide. I thought it had MSMA in it however I don't remember. I know MSMA will cause my bermuda to yellow however I did not mind that I just want the crabgrass gone in a hurry. I might try Drive though if this Weedstop doesn't work.