Q.What can we do to increase the blossoms on our hydrangeas??
We left all the old wood & blossoms from last year. It’s a bit disappointing to not have more blossoms on our 3 hydrangeas.

Certified GKH Gardening Expert
You can always deadhead the blossoms without cutting off the developing buds. Here is an article that tells you how:
https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/deadheading-a-hydrangea.htm
These articles will help with the poor flowering. They may need a boost of phosphorous.
https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/hydrangea-not-blooming.htm
https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/do-hydrangeas-rebloom.htm