I live in Augusta County, Virginia, in the central Shenandoah Valley.  I bought this 2-acre property in 2010 to create a Joel Salatin-style sustainable farmstead.  I had finally got ahead of the bitter lettuce invasion, when this year up popped something even worse, and I have not been able to identify the monster.  It has taken over the whole property during this rainiest summer on record, even thriving in knot holes on landscape railroad ties. 

It starts out a tall and thin single stem, with a soft plume on top, with narrow leaves all the way to the ground.  It quickly reaches up to a six feet tall column, then starts to set buds.  The buds have not fully opened, but I want to cut them off before they set seed.  I have attempted to upload pictures, since I am not good at description.  If that didn't work, here are links to the pictures on photo bucket.  Click on this link, then click "slide show"  http://s1216.photobucket.com/user/glory_be_farmstead/media/101_9979_zps8b9249fe.jpg.html?state=copy