The year before last summer, I picked all the flowers off my hydrangea (I think in September) to dry them. Last summer, the plant did not flower.
This summer, it is blooming again, beautiful deep pink flowers. Is it OK to pick them, or was that the cause of the non-blooming?
You don’t say what kind of hydrangea you have but it is possible that by cutting off all the flowers two years ago, you did also remove the flower buds for the next season. If the plant you are describing is a big-leaf hydrangea (Hydrangea macrophylla), which I believe you are: these big pink, or blue mop head plants, or white lace-cap ones flower on the previous year’s growth. Their buds set late in the summer, so cutting the plants back in September would have removed them.