Yes, it is a Ozark Sundrop. I recognize it because a neighbor had it, and regretted it. It is a very vigorous grower than some descrice s invasive, especially in good soil. It grows a very large taproot and is difficult to divide or relocate. Perhaps in pots?
Thanks Donna. I have seen conflicting reports re its "invasiveness". But you did get me thinking and doing some more searching. Specifically it seems that Oenothera fremontii "Shimmer" or "Lemon Silver" looks very similar but with 'better' foliage and (much) better behaved.