Almost impossible to answer without knowing what pre-emergence you are using. Some only last a month or two, while others can last up to six months.

Any help with this? I sprayed it a few weeks ago with ortho weed b gon for southern lawns (I highly recommend it) and it started wilting within 24 hours. However, there was so much of it that it will definitely require a 2nd application. It hadn't rained in awhile and the weeds that were left were starting to wilt. It poured down rain all day yesterday and that definitely gave this weed a second wind. The pictures I posted are mild compared to how it is in some parts of my yards. My grass looks great besides this. One small fact in case this helps with the identification. The one thing I noticed is this weed started growing weeks after other weeds. It required a higher temperature to "wake up" then most other weeds. Any help would be appreciated.

Oh the grass is there. Look harder. If that is at least 14 inches long, then it is King Ranch bluestem. For years the state has been planting it in the medians along all the interstate highways. Now it is invading everywhere. I have a house in George West which is trying to be invaded by the KR bluestem. I am surrounded by it on 1 acre and it had made inroads before I bought the house. I have allowed my St Augustine to grow unmowed and that seems to have stopped the weeds. I do not have enough of the bluestem to experiment with keeping it mowed as a turf grass. If it would stay down, it might actually make a nice, native, lawn. The color is good. The only problem is the seed stalks.

I watered this past weekend for the first time since all the May rain. I have an in ground sprinkler system and will be waterin 1" a week. It takes about 90 minutes a zone. I have been following the bermuda bible to the best of my knowledge. I mow it with my riding mower at about 1-3/4" every 3-4 days. I put down halts crabgrass preventer towards the end of Feb. But I guess I was to late. Once I pull up all this crabgrass can I apply some more pre-emergent now? Also I fertilize every 30 days with the scotts for souther lawn mix the one with the high nitrogen content. This is what my lawn looked like 3 weeks ago: