Woolly Cupgrass Makes Its Way Into Fond du Lac County Mike Rankin Crops and Soils Agent UW Extension - Fond du Lac County Be on the lookout for a new weed problem. Woolley cupgrass is here and probably isn't going to go home.
Several characteristics make woolly cupgrass difficult to manage.
The seeds germinate over a wide range of temperatures so woolly cupgrass can germinate early in the spring with additional flushes occurring throughout the season. The large seeds germinate from up to four inches deep and produce large, vigorous seedlings. Also, the seedlings are more tolerant to several soil applied herbicides than giant foxtail, which has made control difficult. Uncontrolled plants are prolific seed producers. Single woolly cupgrass plants can produce over 150,000 seeds.