Why does your Hydrangea macrophylla Magical Emerald have white cottony spots? Diagnose the cause and fix it with our step-by-step guide.
These small, soft-bodied insects produce a white, waxy, cotton-like secretion to protect themselves. They feed on the sap of Hydrangea macrophylla, often clustering near leaf axils or new growth, which can lead to leaf yellowing and stunted development.
This scale insect species forms large, white, fluffy masses on the stems and leaves of hydrangeas. They extract nutrients from the plant's vascular system, which can cause 'sooty mold' to grow on the honeydew they excrete.
While typically appearing as a dusty film, certain stages of powdery mildew can look like white patches on the leaf surface. This fungal pathogen thrives in the humid microclimates often found around large-leafed Hydrangeas.
Your plant might also be experiencing one of these issues:
English
Italiano
