Purple Loosestrife, a non-native, highly invasive species, has been added to the USWildflowers database (8/11/2014.)  Scientific name is Lythrum salicaria.  Photo below was taken along the Ohio River in Newport, Campbell County, KY on Aug 5, 2014. Go to the Purple Loosestrife detail page for more photos and information.

Purple Loosestrife – Lythrum salicaria