have had cornflower.. bachelor buttons for decades .. self sowing annual for me ... in the garden.. if you grow the blue long enough .. and have lots of plants .. the genetics will start to regress .. if thats the right term.. and you will end up with a few white.. pink .... and purple ones ... but you would have to have 100s of them to probably start seeing this ... ken

That one is very common in southern Arkansas, and is usually growing in shallow water - creek flats, pond and lake margins, etc.

Here it is, but can't get the focus quite right -- clicking on the pic(s) seems to give a slightly better quality pic. That's one stem, and the stuff to the left is another of the same-type plant -- that one is ~6 ft tall: Your suggestion of Teucrium canadense for the second plant looks to be correct. Thanks. Might have to resubmit a pic of the first plant after it flowers...

Here's a page of links to resources for southeastern plants (although some of the links seem to be dead). A good basic wildflower book is Newcomb's Wildflowers, although it's for the northeast so you'll probably see things that aren't included. It's a good place to start, though. A good technical manual for the southeast is Weakley's Flora of the Southern and Southeastern States; it's out of print but you can download a pdf. It's not for beginners and it's not illustrated, but it's complete and you might find it helpful if you've already got an idea of what you're looking at. I've only used it for grasses. (Actually, other people might be interested in this - a hard copy of this book is probably over $100 (and it's out of print) but you can download a free pdf.)