Q.Why do only some buds on hydrangea paniculata open?
We moved into our house almost 4 years ago. The property had 3 large hydrangea trees (sorry, I do not know which type of paniculata). We were so busy remodeling the first 2 years that we didn’t pay that much attention to the outside, but last year I noticed that although there were lots of bud on the trees, only about half of them opened. We pruned them early this spring and there is the same issue. What can we do?

Certified GKH Gardening Expert
I would suggest bone meal to boost your phosphorus level in the soil, as this may be low. Here is more information on reasons hydrangea won't bloom: https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/hydrangea-not-blooming.htm