You did a nice job on the photos, giving a clear look at the entire plant. The only suggestion I have is for when you take a picture of a tree or shrub. Take a picture of the whole tree/shrub, then take a closeup of the leaves/flower/fruit. Though it's not a guarantee, the detail can be very helpful for identification.

We call it Swamp Sunflower out here. Grows in the ditches and wild places. Continues to grow from the roots as well as drop seeds. Hardy. Perennial. Comes back faithfully. Can be cut back so that it stays lower to the ground if you only want flowers 18" high for example. Single stems easy to pull out if you want it thinned or have stragglers you don't want. Flowers are long blooming and look nice. Repeat bloomer especially if you deadhead. Heidi

It's an Aureolaria, aka false foxglove. They are semi-parasitic on the roots of oaks, even though they do have chlorophyll. Aureolaria laevigata is native here in TN. There are several species, fairly limited in range, so you might have to research which one you have. It's a beautiful plant, and harmless to the oaks they grow on.

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.)