Where do you live?

The directions I'm looking at say,

"Spray when most of the day is expected to remain cooler than 90 ÃÂ F."

That's vague. But still, in my neck of the woods we won't have a day like that until October sometime. On the plus side, you do have bermuda. You might test a small spot before doing a large area. Try spot spraying in the evening after the temps cool down to 85. If bermuda is going to be stressed, it doesn't seem to show it for several days.

Now how are you caring for the bermuda that let the buttonweed get established? Are you mowing it too high (higher than 2 inches) or not mowing 2x per week or not fertilizing monthly???

Thanks for the follow up dchall. I live in eastern nc. Out of the last 30 days it has rained 20 of them. Pretty good rain at that. Probably 8 inches or more. I try to cut my grass every 4/5 days weather permitting. I can't really cut lower than 2 inches without scalping in a lot of places. I'm in the process of leveling out my lawn. I've been reading all of your advise on the subject. I've been trying to find the list where the guy leveled his yard and it showed his contraption he pulled behind his lawn tractor. I can't find it anywhere. If any one has a link I'd appreciate it. Back to the button weed. I fertilize my lawn every month but every time I do we get a bunch of rain days after. I've only lived here 4 months. House been empty for two years prior. My fertilize guy sold me some triplet to spot spray on the weed and it work kinda. Hurts the grass a little too. But it is spreading out of my control. That is why I'm looking to use a hose end sprayer for a larger application. Any help would be Appricated. Thanks.