This grassy weed is definitely in the undesirable category. The blades of grass are course to touch and are a silvery lighter green than Fescues and Bluegrass types. It is a warm season grass and is usually found on South facing lawns and along edges because it spreads by seed and stolons. The windmill seed head will dry up and roll around just like a tumbleweed so it shouldn’t be a surprise it can spread quickly. It tends to grow in clumps and Tenacity is an herbicide that will kill it but it takes more than one application of this specialty herbicide.

Here is a picture of a clump of Windmill Grass while dormant.
EcoTurf of Northern Colorado

1101 Automation Drive #664
Windsor, CO 80550

Servicing Northern Colorado including Fort Collins, Loveland, Greeley, Windsor, Eaton, Evans, Johnstown, Severance, Timnath.