well, all the evening primroses seed like maniacs so......take your chances, I guess.

You may call it Ozark sundrops - I just call it a nasty weed....but I also have bad thoughts about verbena bonariensis, still a beloved plant in my neck of the woods.

I am just putting it out as a possibility i.e. an ID of O.S.

Another possibility is Oenothera fremontii "Shimmer"?

I have posted a close-up of one of the flowers from this same church plant.

(Maybe being in a colder zone like mine i.e. zone 5 will help keep it in check?)

Although I do like those flowers and the compactness of the plant (height) you have got me thinking twice due to its ability to spread. Looking a bit more into evening primrose I see a promising Canadian introduction known Oenothera fremontii AKA 'shimmer' or 'lemon silver'. Many sites make mention of it being much better behaved then other evening primrose. I see no mention of it on GW.

Compare it to my Oenothera missouriensis in the pic here. I have had this in my gardens for about 14 years. It is not a speader like some of the other primroses. Every once in awhile I find a seedling which makes me very happy. I transplant it to another spot. I do deadhead most of the spent flowers most of the time, just to keep it tidy and flowering longer. I don't get them all and late in summer when it has a second or third flush of bloom, I stop deadheading, hoping for some seedlings.

ah well, these are neat little things - not the 5 foot tall bane of my allotment (along with mallow)with an enormous root and a trillion seeds.
Weirdly, I have failed to grow the white EP, pallida and even struggled with Siskyou pink....yet these horridly yellow things need zero encouragement to grow into gigantic clumps.

Smells nice, though.

Missouri evening primrose spreads by runners and is nearly impossible to contain here in north central CT. That being said, it's easy enough to yank out the ones you don't want--I just don't need the extra chore on my gardening To Do list. I don't know if it's listed as invasive but it was already established when I moved here. I rip lots of it out every year. Not even corrugated cardboard topped with bark mulch slows it down.

Yours does look the same as my picture gazania. Thanks for posting. You have reassured me that it can be kept under control.

I am curious as to when and how long it blooms for you.

The first bloom flush begins in early to mid June and lasts about 1 month. It rests maybe 3 o 4 weeks and then sends out a few blooms here and there till a hard freeze. Those big poppy sized lemon yellow flowers make a show even if there is only 2 o 3 of them at a time. This is a perennial that I would not be without in my flower beds.

I am having a hard time believing that I and some of the posters above are talking about the same plant. I can honestly say that the number of volunteers that I have come upon from the Missouri Primrose has probably been less than a dozen in 14 years. My mounds of it have stayed at around 2 1/2 to 3 feet so they aren't spreading by runners. It dies back to the ground in winter.

Be aware that those flowers only last a day, opening in early evening and dieing off by evening the next day, to be replaced by new ones.

I deadhead by taking the flowering stem off at bottom of the seed pod that forms at the base of the stem where it attaches to it's trailing branch. I don't get them all, as I garden from a handicapped scooter, and can't reach those at the back of the mounds.

Oh Gazania - my EP is the lolloping O.biennis, not the neat little O.missouriensis - an altogether different proposition.