Glyphosate won’t control Sericea lespedeza. Check out the following link for some good information about controlling Sericea. You are correct that there will likely be a huge seed bank. It typically takes me two to three years to get Sericea controlled. I have had success killing the existing Sericea and then planting Roundup Ready beans and controlling most of the Sericea. This required spot spraying the larger patches of Sericea with herbicides in addition to glyphosate.
December 15, 2015