It wouldn't be overwater would it? You said 'regularly' instead of 'daily' so I didn't think so but...

Did the croaking point come during a heat spell? Is the shady area a hot one or does it cool down as soon as its in shade? Does it get good air circulation? Did you notice any mildew issues before its demise?

Soil not draining properly?

Competition from tree roots?

Maybe you can give bit more detail and we will try and narrow down the root of the problem ;-)
CMK

The final straw came during the recent heatwave. It's possible I may have overwatered (it does say it likes moist soil!) but that was in response to the fact that it was slowly losing its leaves. The spot is next to a brick wall with a brick path on the other side, no competing roots and good soil with decent drainage. Direct morning sun (northeast corner of house and bright shade the ret of day. So annoyed because it was a decent sized specimen as well.

I planted 3 of these last year in what seemed like ideal conditions, very similar to what you are describing. All 3 of them died within a couple of months. Granted, it was extremely hot and dry last year, but I did try to keep them watered. Still not sure what might have happened in my case...

My guess would be overwatering. Mine rarely get any supplemental water and they do fine. Some of them are looking stressed in the dry period we've had this month so some have got a bit of supplemental water. I expect them all to recover. A first-year plant would need more water but too much would not make them happy I think.

IME, it is one of those 'shade' plants that does much better given a lot of sun. So the one that is still alive, and doing well is in an area on the shady side for peonies.

I have to agree with mad gallica. I've never grown any of these as real shade plants and I've never had a problem with them dying.

However, I must admit almost all the info out there on the web keeps mentioning these as shade plants. I did come across a couple of mentions that the farther north you live, the more sun these can take, so maybe that's the key.

I know a while back I came across a photo of a huge stand of Hillside growing in absolutely full sun, but I couldn't find it today when I was searching.

Kevin

Now you tell me..........virtually everything describes these as shade plants!

Miclino - I bought some sort of veronicas last spring... FULL SUN it said up and down the label. I must have bought 5 or 6 of them. After a few days in full sun they started declining... a few weeks all but one were gone. Dug up the remaining one (or what was left of it) plopped it in full shade and today its growing happily. Its "one of those things" I guess. I feel your pain

I have various types growing in shady conditions - but not the deepest shade - and they do fine.