think about this, once again I never said nothing would grow with the ground covered if you remove the overhead canopy, but any seed germinates when the ground hits a certain temperature, the ground cover acts as insulation to keep the springtime sun from warming the ground, stuff germinates sooner on bare ground, come up sooner and gets a jump start over growing in areas with the ground covered.
and enjoy your ash trees, they will be short lived when the EAB hits there.
RR