What's eating my hydrangea??
by
Layla
+3
slugs? There are no visible bugs on my plant or under the leaves.
It may be a fungus.Treat it with a systemic fungicide
Mites, spray with seven dust under leafs
FULL ANSWER
Black spots caused by fungus typically start toward the bottom of a plant and slowly work upward until the entire plant is affected. Spots are characterized as circular and small and, in most cases, are scattered throughout each leaf. Minimizing leaf wetness by watering only at the ground can help control the spread of this fungal disease, as can removing dead and dying foliage from the plant and around its base.
Neem oil!!