The seed head is a loose spike-like panicle. Nimblewill is found through most of the Eastern United States. Nimblewill is aggressive where the turf is not fertilized. Nimblewill is more aggressive in shaded areas. Turf that is mowed low will resist the invasion of nimblewill.
Nimblewill is more aggressive in moist rich soil.
Make your postemergent herbicide application to nimblewill that is actively growing and in the 2 leaf to the flower stage of growth.