branches on spirea bush grey and curly

Question

The end of the branches of my spirea bush are light grey and curly. I have had the bush for over 30 years and have never seen this before. What is the cause and how do I treat it?

Answer 1

It sounds like powdery mildew.
Here is a link with information on how to control it.

https://www.gardeningknowhow.com/ornamental/shrubs/spirea/growing-spirea-shrubs.htm
https://www.gardeningknowhow.com/plant-problems/disease/powdery-mildew-homemade-and-organic-remedies.htm