They are hard to pull out and will really take over the yard. Happened 2 years ago and finally resorted to spraying bad stuff. Would like to be organic. Any luck? I tried vinegar in some small areas but I am afraid it will kill the grass too. My St. Augustine has some green in it.

Use vinegar. I have made a shield (for lack of a better word) out of cardboard. I cut the cardboard all the way through in half. In the middle of the cut I made a hole with half the hole in one half and half in the other. Then I can enclose the weed in the hole with the grass protected and the weed sticking out. Then spray with confidence knowing that overspray will not hurt the grass.