Why won’t my Hydrangeas flower?
The plant is quite large but hasn’t produced flowers in 2 years straight, and it’s really healthy.
Certified GKH Gardening Expert
It, more than likely, has everything to do with the type of hydrangea that you have, and your climate zone. If they die back to the ground every year, and don't flower, then they likely flower only on old wood. If there is no old wood, then there will be no flowers.
Other issues can include too much nitrogen, or not enough phosphorus and potassium in the soil.
This article will offer more information: https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/hydrangea-not-blooming.htm
This article will offer information on the proper care of hydrangea plants: https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/growing-hydrangeas-hydrangea-care-guide.htm