Brown spots on hydrangeas
My hydrangeas look terrible this year. I did not prune them this past year, yet they died back to the ground, therefore no blooms. Now they look terribly unhealthy. I had the exterior of the house painted in April when they were just coming back, but I have never seen these brown spots all over them before.
It looks like your Hydrangea is developing symptoms of a leaf spot disease. This can be common in wet seasons. Hydrangeas and different cultivars vary in their susceptibility. We have gotten several reports of this.
Fungicides are not recommended as you would have to spray all season. Avoid overhead watering and remove heavily spotted foliage during the growing season. This is not practical if most of the leaves are affected. Simply remove any fallen leaves from around the base of the shrub at the end of the growing season. These sanitation practices will help to manage the disease from year to year.