Hydrangea Preziosa.

Oh, that is Preziosa! Mine has a mix of sterile and fertile blossoms so I didn't recognize it right away. Mine were opening pink and when I added Aluminum sulfate they started opening Violet. I love the colors on this hydrangea both ways, it is one of my favorites (I have many favorites though!). The flowers look very nice and they are a good size too!

:))