Was thinking Joe Pye,but the flowers didn't seem to match my weed book.   I believe  the one we have is Spotted Joe Pye . Going to have the county agent drop by and check it out.  You got me on the right track.  The fact that glyphos doesn't do it much damage is a concern. Although the corn herbicides held it down.

    Thanks for all the replies. Something different I will post back.