In message , Cheryl Isaak
writes
You don't say where you are, but could it be this

http://plants.usda.gov/java/profile?symbol=POPE3

I'm reluctant to offer a positive identification (I'd guess at some form
of willow-herb), but it's not Persicara maculata (I presume that
Polygonum persicaria is the same thing).
--
Stewart Robert Hinsley