My lawn has tall fescue grass. About a quarter to one-third of my front lawn, as we as one-half of my back lawn appears to be taken over by one kind of weed. What type of weed is it and what type of weed killer can I use to eradicate this weed from my lawn? Through the spring and first part of the summer the weeds were pretty nonexistent, but the last couple of months the weeds have been growing and spreading. I used a Scott's weed and feed in the spring but have been apprehensive in using anything else until the fall since it is recommended not to fertilize tall fescue grass during the summer, and not knowing the type of weed growing in my yard, I was not sure what type of week killer to use.