I used Scott's Turf Builder on my lawn, along with lime in mid-March. In early May, I used Scott's Weed & Feed, but no more lime. I had a great looking lawn for about a month. Then in early June, this "weed" began to take over. As of now, it covers half of my front year and parts of the side and back. Based on the pictures on you website, it looks like Lespedeza, but not sure (photo included). I cut my own grass with a riding mower about once a week and let the clippings lie. My question: Is there any lawn product I can use to kill this growth, but save the grass?
This is Japanese stiltgrass or stiltgrass. It is a foreign invasive grass. The most effective approach is to apply a crabgrass pre-emergent herbicide in early spring. You'll want to choose a product with the specific ingredients that are most effective. Here is our webpage with explanation and suggestions: http://extension.umd.edu/hgic/problems/japanese-stiltgrass