I have two (actually three as I incidently split one of the two in two pieces) from the Hovaria (called Kaleidoscope in US) series.
One of them (largest) was overwintered in a pot and another two went straight into ground.
All three in buds as of right now, however, potted one have much more, but also much smaller buds than those in a ground. No dieback was observed on either, but winter was fairly mild and I have just very little of dieback on hydrangeas this year, in general.

George, this hydrangea seems to be a good performer, at least in CT. Why do you suppose they are not more readily available? Last summer's blooms on mine were at least 12-14" across on 3' shrubs. ES seems to get most of the attention for a hydrangea that blooms on new wood but if anyone is looking for something different...'Homigo' is a great plant and an easy keeper. I was impressed in last summer's dry spell that it didn't droop its leaves mid-day like I'd expected either. I had many stems that survived the winter, but not all did. I got tired of waiting for the one year old wood to leaf-out since the new stems were growing so fast...so I chopped the old ones off about 10 days ago. It's the new growth with the buds. From your description...it sounds like I should have been more patient with the old wood.