I usually leave the existing blooms alone and let Mother Nature take care of their deadheading. She usually does that in the 1st quarter/2nd quarter of the new year. But it is really up to you. If you do not like the color that they currently have then feel free to deadhead them early. I just like leaving them for winter interest.

Deadheading a hydrangea does not encourage additional flowering so it's your choice whether you do so or not.

Ok thanks. i just watched a video and the gardener said deadheading does promote flower growth?? maybe i misunderstood ill have to watch again later. its easier for me to leave them. one less thing on the pre vacation to do list.

Blue Enchantress and the Endless Summer Series of hydrangeas are advertised as being rebloomers but they are actually remontant hydrangeas: you get Spring 2021 blooms from the 2020 stems if they survive winter 2020-2021 (note: the 2020 stems develop flower buds for Spring 2021 at the end of the summer 2020 or early Fall 2020); you get re blooms in the summer time from the new stems that began to grow in Spring 2021. Both "flushes" of blooms can be left on the plants until they start to fall down on their own in 2022.

I think Hamptoms only blooms once from old 2020 stems. If you were to deadhead it now, the shrub would remain without blooms (green leaves only) until Spring 2022.

@luis_pr Thank you for your detailed answer! I will leave them all alone then. As a new gardener, hydrangea types and pruning etc are very confusing. Thank you for your very clear answer.