Hydrangea turned green! Help

[iamreginaphalange]

It was blue... over time - 3 months it turned green.
It lives on window ledge in the living room...gets morning and day shaded sun..
What can I do to turn it blue again?

Are you saying the blue flowers are turning green, or new flowers are developing which are green?

You can buy Aluminium sulphate from the garden centre to help maintain the blue in hydrangea. They like an acid soil so you could report into ericaesious Compost. I think mine used to be green white when they first emerged and coloured up a bit later.