If you are having trouble getting blooms from your established hydrangea plants there are several possibilities of why this is happening.
Bigleaf hydrangeas prefer light shade/filtered sun. Too much shade can hinder blooming. Too much sun can cause stress for the plant.
Pruning at the wrong time can remove buds for the next year and prevent blooming. This varies by species/cultivar so you need to know what type of hydrangea you are growing. Some cultivars develop buds on past season’s growth while others develop on new growth.
Well-drained soil is essential. Compacted soil can prevent the plants from receiving moisture even if you are providing enough water. Over and underwatering will impact flower development and plant health overall.
Too much nitrogen fertilizer will support leaf development but not flowers. Fertilizers with more phosphorus will support flower growth.
*** Winter temperature is commonly a problem with hydrangea blooms. If there is a cold snap and no snow insulating the plants along with inconsistent weather (unseasonably warm, followed by a freeze) the buds that developed in the fall can be damaged and this will impact the spring bloom. A late spring frost can also cause problems. If you think this is likely the problem, you can try wrapping the plants as we head into winter to provide some protection.
Your local extension agent can help diagnose further based on the historical weather data from your region.
