Mid-Atlantic Gardening: HELP ME ID THIS PLANT!!!!, 1 by Gitagal

Gitagal wrote:
And--lastly--here is the stem of the cutting he brought....
As you can see--it is reddish.

My first thought was that it is a Joe Paye Weed----BUT--WHY would have I given him a root of this?????

Does anyone remember if I could have picked up a root of this plant at a Plant Swap in 2008???

Please give me your best guess.
If you cannot ID it--I will post this on the "Plant ID Forum"....

Thanks--Gita