I have 12 nepeta scattered around my garden. All same variety (Summer Magic). Some were some of the first plants to emerge around Mar 2nd and some I thought were dead just started emerging last week, so seems like each one has a mind of its own. Location didn't seem to matter either. Some of the Mar 2nd ones were right next to the late ones. Seems odd all 6 of yours would die though considering how generally tough those plants are, so maybe they are just taking their sweet time!

I garden on loam

and Nepetas are one of the species that tend to die on me over winter.

do you garden on sand?

and Heliopsis were not great with fall planting either for me

slugs can get them/Nepeta when the shoots emerge and the bed is somewhat crowded IME

had the same problem with Caryopteris, they croaked after fall planting (like, 4 or 5, over some years)

the last two I planted in spring and they resprouted after their first winter

added: and I got a weedy patch near a large apple tree that I always mean to but never get around to planting/seeding grass there, as a bed wont work near this huge tree

among the self sown stuff are two Nepeta volunteers growing happily and almost starting to flower now, I guess the tree roots help to keep the soil dry-ish for longer

I'm reporting that my Nepetas, all Walkers Low, have been thriving in heavy wet clay. Highly unexpected.

My Walkers Low are also happy in heavy clay. I only grow Walkers Low because it does so well here (I have 9). Its one of the earlier perennials to emerge and blooms right after the spring bulbs.

Well, I garden on lean, sandy soil...which is why I planted a bunch last year. I do have slug and snail issues, but for all of them to have vanished is a bit...well, I don't know what to think. I grow dahlias with no real problems although the tubers live in the ground and are large and vigorous enough to simply shrug off snail munching.

The heliopsis were seed raised and have always been a tiny bit problematic, although I will be sad to lose them (Bleeding Hearts, a truly lovely colour).

I know the callirhoes are fine cos I can see the top of the crown (and feel the enormous roots attempting to burst out of their pots (due for transplanting soon). Less sanguine about the small sisyrinchiums (I raised a heap of bellum, idahoense, palmatum - not the weedy striatum...which is immortal).

That’s a bummer! When did you plant them? The ones I planted early Summer are all coming back, but the ones planted in early Fall, not so much. 😔

Terrible time for planting, mazerolm - around midsummer, but I was conscientious with watering (unusually). The weather is horrid today or I would be out, grubbing around to see if there are any sign of roots. Slightly concerned about echies now (not fancy ones,just standard purpurea).

Grrr, ordered another half-dozen And geum, angelica, crambe, polemonium...

My Walkers Low has come back for a few years but I am in a warmer zone

I would not underestimate slugs killing powers on tender young perennials with little root mass. Do you use slug pellets or anything?

I am not underestimating now, lin! No, I don't use slug pellets because I get songthrush and stormcocks on my plot (I have a lot of dense cover and provide water and a coupla flat 'murder stones'). Anyway, new plants arrived from Dorset Perennials.Floral, have you ever tried this nursery - they are stupendous in regards to flawless plants, in top health and vigour and cheap? Cannot recommend them enough.I will be protecting the new plants with cloches and fleece until they are established.

A word of caution. If your Callirhoe bushii becomes a thug, better to remove it sooner than later. It's right up there with Aegopodium and Creeping Jenny in level of unpleasantness. My C. involucrata is the comeplete opposite, weak and feeble. I'm going to try growing the species native to Illinois, Callirhoe triangulata. It thrives in dry sand and is supposed to be much better behaved. I hope your Talinum shows up. They are a treasure wherever you find them. I've grown Talinum/Phemeranthes calycinum for many years, but only a couple plants actually appear every year. The Callirhoe carnage continues. Besides the main bed , there are many growing from seed in other beds. Explosive seeds?