Here at Watermark Woods we have some huge problems with invasive plants. We pull them out as best we can, but they always seem to have the upper hand. The article below has some great advice on how to regain control. One plant We love for this is Packera aurea. It is a profuse bloomer and a hearty spreader! We are finding that it is one of the few plants that can overcome japanese stilt grass.
http://www.humanegardener.com/how-to-fight-plants-with-plants/