It is another bad fall for Windmillgrass (Chloris verticillata) in Iowa lawns. It is producing seed heads right now (Oct. 1) and is more readily visible than at other times of year. It is a perennial and is hard to kill. Tenacity (mesotrione) is labeled for windmillgrass, but it takes persistance to get rid of it. It's biggest problem is that it acts like a tumbleweed. These seedheads will dislodge from the plant soon and the wind will roll them over the lawn. This allows them to spread their seed very efficiently.
Here are some new pictures that i took close to my home near Nevada on Sept. 26, 2017. I hope they don't roll my direction.
For more information on this species, search the older turf blogs on this site.