Brown and curled leaves on lilac - Ask Extension
All of the leaves have curled and turned brown on my lilac bushes. Everything around them is healthy. There are no pests that I have noticed. We have...
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Brown and curled leaves on lilac #880905
Asked August 10, 2024, 8:13 AM EDT
All of the leaves have curled and turned brown on my lilac bushes. Everything around them is healthy. There are no pests that I have noticed. We have had quite of bit of rain. I have noticed that this is happened to most of the lilac bushes in the neighborhood and beyond. Have you heard of something that could be causing this, just north of Minneapolis?
Anoka County Minnesota
Expert Response
We have had many questions in Minnesota this year regarding lilac leaf diseases, especially from the southern part of the state. If you search old questions, I'm sure you can find a few answers by me and other Master Gardeners.
We cannot identify these diseases from photos. For one thing, many of them have similar symptoms. Here are some links to information on a few of these diseases:
https://extension.umn.edu/plant-diseases/leaf-spot-diseases-trees-and-shrubs#bacterial-leaf-spots-and-blight-1156513
https://yardandgarden.extension.iastate.edu/encyclopedia/lilac-bacterial-blight
https://yardandgarden.extension.iastate.edu/article/2021/08/summer-foliar-lilac-diseases
If you want to identify exactly what your lilac has, send a sample to the plant disease clinic:
https://pdc.umn.edu/
However, in most cases, your lilac will survive, although bloom may be reduced next season. And some simple disease management tricks (careful fall cleanup, water management, good air circulation, etc.) will help in the future:
https://extension.umn.edu/plant-diseases/leaf-spot-diseases-trees-and-shrubs
Many of the lilacs we've been asked about are quite old. Older lilacs can often benefit greatly from renewal pruning (remove 1/3 of the old wood each year for three years). You might consider starting such a program next winter:
https://www.extension.iastate.edu/news/2006/jan/072602.htm
We cannot identify these diseases from photos. For one thing, many of them have similar symptoms. Here are some links to information on a few of these diseases:
https://extension.umn.edu/plant-diseases/leaf-spot-diseases-trees-and-shrubs#bacterial-leaf-spots-and-blight-1156513
https://yardandgarden.extension.iastate.edu/encyclopedia/lilac-bacterial-blight
https://yardandgarden.extension.iastate.edu/article/2021/08/summer-foliar-lilac-diseases
If you want to identify exactly what your lilac has, send a sample to the plant disease clinic:
https://pdc.umn.edu/
However, in most cases, your lilac will survive, although bloom may be reduced next season. And some simple disease management tricks (careful fall cleanup, water management, good air circulation, etc.) will help in the future:
https://extension.umn.edu/plant-diseases/leaf-spot-diseases-trees-and-shrubs
Many of the lilacs we've been asked about are quite old. Older lilacs can often benefit greatly from renewal pruning (remove 1/3 of the old wood each year for three years). You might consider starting such a program next winter:
https://www.extension.iastate.edu/news/2006/jan/072602.htm
