Virginia Dayflower, a native species, has been added to the USWildflowers database (09/30/2012.) Scientific name is Commelina virginica. Photo below was taken in Walker County, GA on Sep 26, 2012. Go to the Virginia Dayflower detail page for more photos and information.
Virginia Dayflower – Commelina virginica
The Virginia Dayflower blooms in my yard every summer since we moved here which is 21 years. Is this unusual? Our yard backs into a passive park in Richmond, VA. A tiny creek is in our yard also.
Not speaking as an expert, but I wouldn’t think that having a colony of a plant such as Virginia Dayflower survive in a location for that period of time would not be terribly unusual, especially if you are not making any effort to rid yourself of it. I’ve got plants on my property I’ve been trying to get rid of for 30 years unsuccessfully. 🙂