T o Answer your question SBG -it was under light shade in a fairly dry site and I did not water it this year its 3rd summer.

I had to move my Lady in Red mid summer Drc, which was obviously a bit of a risk. Despite me thinking I was watering enough the leaves on mine did the exact same. I doubled what I was giving it and it solved the problem.
I was surprised at how shallow rooted it was, could be drought as you suspected. Mine is still in full leaf too.

In spite of watering it since July and all the rain recently all the leaves still look like the above Scottish and yesterday I moved it just to see what happens.

maybe its a bit late in the year drc and youll have to wait till next spring .

Yes, lets hope it survives the winter NP

I hope it does well in it's new spot Drc. According to the RHS, Physocarpus prefer an Acid/Neutral ph. You would have expected to see some sort of deficiency signs in the leaf rather than them curling like this.

Thats what I thought to Scottish.