Q.Hydrangea
My hydrangea has developed ugly black spots. What is it and how can I control it?

Certified GKH Gardening Expert
This is an ugly blight that shows itself in the heat, or when it is overly wet.
This is hard to control, but can be done.
Cut back all growth during dormancy down to about 1 or 2 feet. This should take out most of the infected portions making it easier to treat.
Next you will treat with a fungicide. This article will help: https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm
I would also recommend treating the ground with DOLOMITIC LIME and WETTABLE SULFUR to ensure that what is left in the ground gets treated. It will be handy to keep these two things around, as they are good methods of solving infections in plants. They can be used once per year to prevent issues, or when ever you need for spot treatment.
This article will help you to care for Hydrangeas: https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/growing-hydrangeas-hydrangea-care-guide.htm