Crabgrass ID Confusion
One weed that gets confused with Crabgrass this time of year is Dallisgrass. Folks see Dallisgrass in their lawn and the first thought is that their Crabgrass preventer did not work. Dallisgrass is a perennial grass that is common in the south and surrounding states to the north. Since it is a perennial grass, it comes back every year from roots so a spring applied preventer to take care of annual grasses that grow from seed each year does not work. Often the only choice is to kill this grass with a weed killer like Roundup. The downside is that Roundup will kill all vegetation in the area that you spray, however you can seed that area a week later. You may still have Dallisgrass next year because the plants produced seed all summer. The seed heads provide the best way to identify Crabgrass and Dallisgrass.