In one corner, we have Richard Nunnally, who writes a gardening column for Virginia's Richmond Times-Dispatch. He recommends crown vetch (Coronilla varia) to a reader landscaping "several hundred feet of shady, exposed road banks." Mr. Nunnally notes that since the species can be invasive, it "isn't a good choice adjacent to manicured landscape beds." You can even buy seed to grow crown vetch, which the American Seed Trade Association called "an economically indispensable crop," from a number of vendors.
In the other corner (.pdf file), we have the Virginia Department of Conservation & Recreation, which categorizes crown vetch as invasive. In response to a request from the American Seed Trade Association, the Virginia Department of Conservation and Recreation reevaluated 11 species on the List of Invasive Alien Plant Species in Virginia, including crown vetch. Crown vetch, along with 9 of the other 11 species, is still on the list (.pdf file) under "Occasionally Invasive Species."