You must be in some balmy, frost-free location for your hydrangea to be still pushing flowers! Deadheading can be done at will or your choice - many folks leave the old flowerheads in place over winter and then groom or clean up in spring. But then.....most of us do not have hydrangeas blooming in late January unless grown as houseplants :-)

Just clip the old flower off at its base or down to the next set of leaf buds.

I'm in Houston. We had our one and only freeze of the year last week, and it sort of did in the new and budding blooms. Oddly enough the one huge spent bloom looked unaffected, heh. It's done and faded to that lovely taupe color. MAYBE some of the other blooms will come though. We'll see.

I was wondering about deadheading because the stem/stalk that the first bloom was on got top heavy and it flopped over. Wondering if the growth would be strengthened or hastened by not lying on the ground, if I deadheaded it.

Thanks!