Q.Why does my hydrangea tree have no flowers?
This tree grew out from my plants about 4 years ago, and every year it grows really tall in the summer and all the leaves fall off in the winter. I have never had any flowers this year I don’t even have flowers on my plants.

Certified GKH Gardening Expert
There are, actually, quite a few reasons why this could be the case. The most common is the type of hydrangea and where you are located.
This article will help: https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/hydrangea-not-blooming.htm