Got this potted plant as a gift a week ago, the petals / flowers are withering away or drying up , located in front of a big window.how do I keep it blooming and save the plant?
Quick! Remove that foil wrapping. Although hydrangeas dislike dry soil, they also can’t sit in water. I suspect that your plant has been too wet. If possible, remove it from the pot and examine the roots. If they are mushy and a bit smelly, there may not be hope for the plant. If they seem OK but just surrounded by wet soil, repot the plant in new soil, put it in a cool but bright location, trim off the dead and dying parts and hope for the best. If it begins to perk up, you might like to consider planting it out in the garden.
Click on this link to our answer to a previous inquirer, with details on how to do so.
Good luck!