It’s a tricky one Norma. I’ve got a few of them myself. They don’t all respond the same to soil conditions but in general if it is a pink hydrangea it needs an alkaline ph soil the quick way to do this is to add a little garden lime, but don’t overdo it.
However, if yours has lost colour completely it’s probably just struggling with the conditions it’s in. Could be too dry, they need to keep moist.
Lovely plants when they thrive!