I live in Zone 4 Indiana. My Blue Nikko hydrangea did not bloom this summer. Should I leave it alone and wait until next year? Fertilize it when? I have never pruned it back and am certainly afraid to at this point. Thank you.
Blue Nikko Hydrangea
Certified GKH Gardening Expert
The soil around the hydrangea may be lacking in phosphorus. That can affect the ability of the plant to bloom. Adding some bone meal in the soil should help alleviate the problem in the future. These articles will help you learn more (if you haven't already read them):
As for fertilizing and pruning, these articles should help you: https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/fertilizing-hydrangeas.htm