Growing Miscanthus for Bio-mass

With cellulosic ethanol plants coming on line, some farmers will be looking to grow biomass.  University of Illinois has been researching the topic for a number of years and the favorite has always been Miscanthus.  Miscanthus as grown in Illinois is a sterile crop.  It is established by planting rhizomes.  The research is clear on the amount of biomass produced.  What is not entirely clear to me is, is there any possibility that seed could get into the system somehow and create a new superweed.  Remeber multifora rose.