Our Lilac Is Not Well – What Should We Do?

Question

We live in Minnesota and have had this lilac for many years. We had many beautiful lilacs this year, but by the end of summer, the leaves had a white, then purple look. I’ve attached photos. Is this something that will be cured by winter cold, or do we need to take action? Please help!

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Answer 1

It looks like powdery mildew and possibly some leaf spots, too. Neem oil should help. Also, thinning out the canes each year will increase air circulation that helps prevent fungal diseases. Powdery mildew is very common in lilacs and they should recover without treatment. Also, the more sun they get, the better. Lilacs in shade will always have powdery mildew.

https://www.gardeningknowhow.com/ornamental/shrubs/lilac/common-lilac-problems.htm

https://www.gardeningknowhow.com/ornamental/shrubs/lilac/powdery-mildew-on-lilac-bushes.htm