I planted 6 Endless Summer hydrangeas last summmer on the east side of my house (sun to about 1:00 or so, then shaded by house). Three are huge, 3 are much smaller with 1 of those 3 being really small. They were all purchased from the same garden center, but the ones that are now smaller were purchased about 6 weeks after the larger ones. They were all put in the ground at the same time and the big ones looked ratty. They were all the same size. The only explanation I have for the size difference is that the older ones might have been more root-bound, which somehow helped them.

But now what do I do? This is a symetrical planting (hydrangeas mixed with boxwood and some other perennials) and it is not close to symetrical. Should I fertilize the smaller ones (I did add extra compost around them)? They all have blooms, but the big ones have more. Any suggestions are appreciated.