I live in Toronto and have a wonderful if small south facing garden that gets tons of very hot summer sun. My hydrangeas, incrediball I believe they call them that develop huge pink balls, were still flowering to some degree 2 weeks ago due to this very mild fall but last weekend after a week of extreme cold and a dump of snow I went out to dead head them and put protective covers this year, and I discovered that all the branches have many chubby buds but that are in many cases starting to open and actually bloom again! What do I do about this? These buds will die of the cold but if I cut right back I'll get no blooms next year. Last spring I noted that all the little buds that were on the plant in winter (which had been very rigid) had turned black and were clearly dead. I cut it back drastically and they came back but with minimal flowers.
Nothing to be done--once buds start to emerge, it has to happen (there is no pause button). Sounds like it might not be the right plant for the climate there. Have you noticed any issues with similar hydrangeas elsewhere in your local area?