I'd say so. Windmill seeds stay on the stalks where they should ripen to resemble plump blueberries by late fall. In my experiences locally and regionally, windmills don't drop their seeds freely. I've seen then stay on old stalks for months or even years. Even harvesting ripe seeds it takes a deliberate tug to get them off the stalks. Dropping immature green ones is not normal. Not sure what would cause that. Unfertilized? Not viable?

Okay. Thanks wetsuiter.