Hi John,

Plants in the squash family often produce male flowers first, and the female flowers that produce fruit come later. You can spot the female flowers by the swelling at the base of the flower, next to the stem.

What kind of hydrangea is it? Have you fertilized it or the lawn around it? Is it in sun or shade?

If it is a mophead they aren’t reliable bloomers here.

From the internet:

While Hydrangea macrophylla is not considered a particularly difficult plant to grow, it may fail to flower. This may be due to cold winter damage to the flower buds, not getting enough sunlight, too much nitrogen fertilizer, or pruning at the wrong time of year. H. macrophylla forms flower buds in late summer. As a result, pruning in late summer, fall or winter could remove potential flowers.

Do you have a variety name?