Q.Endless Summer Hydrangea Help Please…how Can I Make These More Full And Bigger? They Are So Sad.
Attached is a collage to see progression. Top two show when they were first planted and then a year later. Bottom two show what they look like now. Should I prune? fertilize? Or leave alone? I think I may have overwatered and over fertilized last summer. Help?

Do not prune ES or any Big Leaf Hydrangea yet. The pictures depict a hydrangea going into dormancy. Now wait to see if the stems survived winter. The stems that survived winter will very slowly leaf out much later after the plant develops new spring stem growth from the crown/base. But, it may take until the end of spring in northern areas in your zone 7a!to leaf out. If no 2022 stems survive, the roots will develop new 2023 stem growth that will produce blooms in the summer/fall 2023. If there are no new stem growth or stem leaf out by the end of June (July if near Canada), the plant did not make it. Pinching can be used to make hydrangea stems fuller.