From cuttings I did last summer and wintered over in a warm basement, I'd say not really since I had 3 bloom recently. Just my observation.

There are a few breeds that are supposed to circumvent the deciduous process.

Once recent one is Avantgarde (Savant). Produces a few massive stems and gigantic flower heads. I guess the trade-off is that any type of season change would kill the plant? Don't really know, as North American growers and retailers have been reluctant to carry such plants.

Thank you all for your input. I have a ton of rooted hydrangea cuttings and have been trying to figure out which to overwinter outside, and which to overwinter indoors. I have decided to put the strongest in the ground in August and bring the smaller ones inside in my little mini greenhouse to grow over winter. That way if the winter is horrible and I lose the ones outside I will still have a few inside for spring. They are just macrophyllas and one Annabelle looking smooth hydrangea. Thanks again!

I have seen Macs growing in the Caribbean (the tropics basically) and while it was in the mountainous regions where it is cooler, there was no such thing as freezing temps to worry about there. The flower buds develop in July-August for the Macs, Oakleafs Serratas and Asperas & then they open in the Spring. For the paniculatas, etc., they develop flower buds in May-June and they open in June-July. Too warm for any cold in many places.

Oakleaf hydrangeas leaves are some of the ones to go dormant the latest in Fall. Maybe Nov-December. About a month after my other Macs. Last winter, one oakleaf that I have in a protected location never went dormant and its leaves were replaced by new leaves starting around March. So the ones in the tropics/Florida might do similarly "if they feel like it". ;o)

Does that mean that I can keep my potted hydrangeas in door during the winter without sacrificing blooms the following year?

While hydrangeas do not do well indoors, you can store them in the garage or in a shed... Just do not forget to water them!!! Once Spring arrives, take them outside again.

You can keep them indoors in front of a window if you have a humidifier in the room they are in. Just make sure you keep the soil moist as well as Luis said. Hydrangeas don't like the dry air conditioned or heated air we have indoors as they crave moisture. I've been talking to an old hydrangea guru and she has been giving me advice. lol.

I lost an Everlasting and a Moonlight hydrangea this past winter. I left them in the garage and they never survived....the stems froze and bursted. Did I water them too much that they froze, expanded and bursted? Please help me because I have quite a few hydrangeas that are in pots and would like to keep them in pots until the following spring when they will be planted in my new garden. Thank you everyone for your help.

All plants are made of -amongst other things- water and this will occur to exposed parts as the temps get very cold. If they go dormant, there is less probability of damage but at some point, it can happen if the temp gets cold enough. So not a big deal that the Everlasting stems burst however... since roots are the important part of the story. Prune the damaged stems off in Spring if you want. If the roots stay alive then the plant will create new stems in Spring. That is why they are labeled "hardy to zone 5".

Roots are the things to REALLY care about and since roots are more protected by the soil and mulch and the garage environment, they should make it. But if you already know that this area gets "too" cold, you can use additional measures such as putting an electric heater in the garage, place them near warm walls or try a basement. I suppose you could even try the inside of the home; just remember that hydrangeas do not grow well inside the homes so keep them there temporarily: once they go dormant, put them inside; take them outside around the avge date of last frost for your area (keeping them in a dark location may prevent them from leafing out early)...

Yeah, when we talk about garaging plants here we typically mean "cold but not freezing". You CANNOT expose complete root balls to below freezing temps while in storage.