I have a hydrangea plant that was gifted from my dad off a cutting from one of his plants. This plant blooms pink early, but after the first blooms die off, a second wave of flowers does not appear, and the plant appears to look sickly. I water and feed often, but it still does not bloom throghout the summer. I prune it in the spring.
Certified GKH Gardening Expert
Here is an article or two that you may find helpful: https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/hydrangea-not-blooming.htm