Sorry I have no input but I'm envious you can grow different coreopsis cultivars. I tried many -- they bloomed great throughout the summer never to return the following spring. Only Zagreb likes my conditions, so I have many all over the garden. I would really prefer Moonbeam instead, but what can you do...

I am very dubious about these brightly colored coreopsis to be fully perennial. Even in my very mild climate, they seldom return the next season, behaving more like annuals. It is only the standard yellow varieties (verticilllata, tinctoria, lanceolata) that return reliably.

I am not sure if they WILL grow in my garden yet. I also think they are not likely to last more than a year but I am going to give two a try and see how they do. I haven't actually tried moonbeam or zagreb yet either...they may be in the future as well.

My front bed is filling in with echinaceas now though so I may quickly run out of room....then I start eyeing more grass for removal!

Zagreb is pretty much bulletproof -- I highly recommend it. I grow it in a spot with perfect drainage, and in a spot that gets waterlogged over the winter and spring, and they are both happy, reliably coming back for 7 years now. Moonbeam is more temperamental and short-lived, but that shade of yellow is so pretty!

I grew C. Red Satin and it was lovely - the first year. The following year 1 of 6 returned. I had a group of 3 in two different spots. You are south of me so you might be more successful than I was.

Do try C. Moonbeam & Zagreb. Interesting that so many find Moonbeam fussy. It has been in my garden for years and is my fav. I agree Festiva Maxima that Zagreb really is a strong grower. It needs taming every couple of years because it spreads.

I planted ‘Peach Sparkle’ and ‘Heaven’s Gate’ last year. They looked amazing. They’re rated zone 5 and I am 6. They are dead as a door nail this year. I established them well, too. Absolutely not neglected. Unhappy they died.

I simply don't have any luck with the verticillata group of coreopsis.

All hopeless apart from lanceolata and tripteris - waste of money and effort for me.

I have done well with various lanceolata types, and a whole raft of verticillata types in three different gardens: rosea, Moonbeam, Zagreb, Golden Gain which is taller and larger flowered than most verticillata, and I think a mostly white one. I tried one of the red and gold hybrids where color balance is somewhat temperature dependent (either Red Shift or Route 66) and it’s supposed to be a bit hardier than many of the hybrids. While it hasn’t outright died, it hasn’t ever gotten larger or even filled out well over several seasons, so I haven’t tried any of the other fancy colored hybrids which by all reports I’ve seen are less hardy.

Berry Chiffon has come back reliably for me for the past 4 years, as has Zagreb. Jethro Tull did terrible, and Creme Brulee was wonderful the first year and then never came back.

To be perfectly honest, for some reason last year I ordered Route 66 during a sale. I noticed it yesterday because it's now flowering and it's the UGLIEST coreopsis I've ever seen. So I guess I was incorrect in saying no luck. Lol, well previously no luck has been my luck with the verticillata group.

Long long ago, I grew Zagreb and Moonlight and in a couple of cases had them two or more years...but certainly not forever.

I should have included earlier that ‘Mercury Rising’ has survived two winters so far.

For the Midwest, here is a trial done at the Chicago Botanic and written up in Fine Gardening.
https://www.chicagobotanic.org/sites/default/files/pdf/plantinfo/coreopsis2016.pdf

This may not help Iowa Blooms since growing conditions are so different, but for those near the US east coast, the Mount Cuba Center did a Coreopsis trial in 2012-14.

https://mtcubacenter.org/trials/coreopsis/

Here is a Coreopsis trial done at Penn State though they have each year separate and don’t seem to have done an overall average for a plant, so it is less useful IMO.

http://trialgardenspsu.com/summary.php?menu_filter=species&selected_menu_item=Coreopsis&year=all

I did order the two coreopsis and they arrived today, just as our temps soared into upper 90s. I might plant them on a light sloped area for the drainage properties.

Ah I do enjoy reading plant trials. Thank you for the link NH Babs. I hadn't thought to look for one on coreopsis.

Well yes, nurseries, growers, breeders do hype and push new stuff. I am a fairly reserved and cautious plant purchaser and I do enjoy swapping locally, starting from seed, reading up on plants in general etc. I enjoy some newly released plants too though. A healthy balance can be achieved without feeling like a victim or at risk of losing our soul. :)

I do think many organizations in general are no longer concerned about the integrity of their product but instead their stock or company value is really what they are "selling". More like the consumer is just a rung on the ladder along the way. But we see that in all kinds of sectors, not just horticulture.

Heuchera breeding has also been pumping out so many new releases--many
are starting to look the same to me. But the ones I planted have all
been pleasant surprises for me. I down right LIKE caramel, pinot gris
and circus.

Oh and echinacea. Wowzers! I benefited from this forum a few years ago and avoided the new releases except for some Cheyenne Spirit seeds. Now I have a whole spectrum of lovely coneflowers. I have a hard time culling out the "less desirable" ones. They all have some merit in my eyes! Yes, I am a plant pushover lol!

Ah, for sure, Iowa - the horticultural industry, in all its variance, has held out surprisingly well against many commercial practices (where profit is the sole metric of quality)...but, we, as consumers, have a way of levelling the playing field through forums such as this (indeed, am prepared to put up with the enraging HOUZZ)...since our agendas are not predicated on a 'bottom line'. Here in the UK, education and apprenticeships have been severely curtailed...so passing on knowledge, information, suggestions and advice from other gardeners, has been of huge value...but yeah, still feel a sceptical, rather than outright cynical and jaded (moi), is a reasonable attitude to cultivate, particularly given the shiny, shiny stuff.