Red Car Property: Giant Grass Near Historic Viaduct Footings

Photo: Diane Edwardson, June 6, 2012.  Although it doesn't look so gigantic here, those flower stalks are 6-8 feet tall.  I have no idea what this grass is, but it's spreading over the  mostly shady hillside just past the historic viaduct footings on the Red Car Property. (Click on image to enlarge.)