I am currently trying to find close-up images of the leaves that matches mine. You can see these ridges in the third photo above. I really would like to narrow this down, if at all possible. With this name change, it's making searching a little more complicated because large databases of native plants are still using the Gaura genus.
This shows how important good, clear images of leaves are. I went to Maximilian sunflowers here to add the plant to my list and AAAAH! How many more photos of blossoms of that plant do we need?!