I planted a hydrangea last year and it is not blooming this year. The plant looks healthy and is growing bigger, but no blooms. I am not sure what kind it is other than the tag said Little Prince on it. It gets about 4 hours of sun a day. Why doesn't it bloom?
You may be lacking phosphorus. If there is a lack of phosphorus in the soil, plants will have little to no blooms. You can either use a phosphorus rich fertilizer or add some bone meal to the soil. These articles may help as well: https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/hydrangea-not-blooming.htm