My very healthy looking hydrangea has had no flowers at all this year
It is a white hydrangea and only 2 years old, the leaves are lovely and green, but not a single bloom.
Certified GKH Gardening Expert
This is a common concern with hydrangeas. Absence of flowers is often the result of ill-timed pruning, too cold of a winter, or Too much nitrogen or a lack of phosphorus in the soil.
Here is an article that explains: