flowers are ephemeral.. only lasting a few days or so.. maybe up to a week or so ...

they are aging .. and discoloring ...

nothing to do about it.. but enjoy it... the flowers themselves.. can last a very long time.. even if they arent pretty blue ... and in fact.. can be dried and brought in the house in a dried cut flower display ... but they will be tan colored.. and so could be painted ..

https://duckduckgo.com/?q=hydrangea+dried&t=ffcm&iax=images&ia=images

next time... buy a plant with barely opened flowers ... so the show will take longer to develop for you.. and ergo.. last longer ...

it is a perennial ... and probably should be planted in mother earth for winter .. rather than torturing it as a houseplant ... we can help you with that when the time comes ... depending where you are ...

ken

Ken is always right! Do what he says and next year your hydrangea will be beautiful when it blooms. :-)

debra

Are you keeping it indoors? If so harden it off and put it outside. It’s not a houseplant. Depending on your climate it might need winter shelter and/or summer shade.

P.s. I’m afraid Ken is not always right. Hydrangea flowers should last weeks, not days, in good condition before they fade. Correctly dried they will keep a lot if their colour. Those circular brown spots do not look like normal fading to me. More like a fungal issue.

I agree with floral. And when cut at the right time in their development, blue hydrangeas can be dried and preserved in all of their glory.