Dotted Smartweed, a native species, has been added to the USWildflowers database (12/22/2012.) Scientific name is Persicaria punctata (formerly Polygonum punctatum.)  It  is also known by the common names Dotted Knotweed, and Water Smartweed.  Photo below was taken at the Flintstone Nazarene Church, Walker County, GA , on Sep 25, 2012.   Go to the Dotted Smartweed detail page for more photos and information.

Dotted Smartweed, Dotted Knotweed, Water Smartweed – Persicaria punctata