In my experience, the grass is most of the time still present under the weeds. We had stickweed and ironweed and blackberries galore when I took this place over. So thick it was hard to walk through them. That was late summer 2015. I mowed twice that year. Sprayed spring 2016. Again in Summer 2016. Mowed twice in 2016. Sprayed this past spring. Fertilized with 12-24-24 (Nope, didn't soil test). Have sprayed the bad places this summer. The only thing really persisting would be the horse nettle. That stuff is tuff. Used Remedy this year and it works so well.
Now we have a very productive and very clean pastures. To be honest, they're some of the better looking and performing ground around me. On top of the trifecta of weed control, we started rotating pastures Spring of 2016. It impresses me every time i walk through, so many types of grass and legumes. This property was overgrazed for decades upon decades. Plan to keep cutting paddock size...
Patience is key i do believe. As stated already, it takes time. A few years for sure.
Its doing so well that we have higher stocking rate than my Papaw ever did. Using the exact same acreage. And I am considering very strongly to take about 10-20% of current pasture and make more hay next year.
Its crazy, but
our pastures are more productive than our hayfields
. Reason being that the soil is in better shape. And only getting better. Now I've got to figure out how to make the hay field's soil healthier.
Oh, and we unroll our hay when we feed. That is probably the second best contributor to our soil health next to rotating fields. Has really turned it around.
Understanding soil biology and health is key.