Q.Can 2 like hydrangeas be added together?
Can I dig up 1 hydrangea and plant it along with another already planted hydrangea?
They are both approx. 2 & 3 yrs. old, but I think if I could do that, it would make a nice statement. They both look healthy, but I thought by now they would be bigger. One is planted in sun, the other in shade.

Certified GKH Gardening Expert
I would plant them several feet apart. Hydrangeas, with the exception of the tree hydrangea will not tolerate sun. They must remain partially, or fully shaded.
This article will help: https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/growing-hydrangeas-hydrangea-care-guide.htm