Your task is to keep the root ball moist without freezing. Wrap the pot in a fleece or bury it to protect the rootball from extreme cold. I would suggest transferring the hydrangea to the garden once spring arrives. I just don't think they do well in pots.

Yes, they're deciduous; if its a very large pot, its less likely to freeze, but freezing of the compost in the pot will only be a risk if the temperature falls below zero degrees C night AND day for longer than a week. A very rare occurrence in the UK... last time pots froze (depending where you are) was at least 20 years ago... (probably not true in Scotland)

Keep it moist, don't let it freeze.

Thank you for advise,will wrap fleece round it,pot is not standing on the ground, in a holder which is on legs .Do I put the fleece under the pot too or just around it?
Thank you

Wrap around the entire pot & underneath.

Yes, consider planting it in the garden come spring. It will take care of itself.

There is a drawback with using fleece - when it rains, it gets wet, and if it then freezes, you've got a frozen wrapping round your pot, so you need to remove and dry the fleece if cold weather is coming.

The snow keeps my hydrangeas moist & prevents freezing. The end result is huge gorgeous flowers next Spring. Nature does it all for me.

Hi Bathgate, can you tell me which species of Hydrangea flowers in spring please, all the ones that I know flower at the earliest in early summer, most midsummer into autumn, and some late summer into autumn, I would love to have 1 that flowers in spring, Derek.

I have Hydrangea Macrophylla, Blue Jangles. Bloom time depends on your climate. I also have a white one which was an Easter Decoration from my church - not sure what type. For me, they start blooming in June and holds its flowers all year until frost. In the South, they starts blooming in April.

Hi, I must be living in the wrong place then, macrophylla doesn't start blooming until late summer, into autumn here, but thanks anyway, Derek.

Late summer? wow!

thank you all.