Lilacs dying? - Ask Extension
The leaves on my lilac bushes have already turned brown and dropped. Same is true at my neighbor's house. Is it the heat? Is it a disease? If I trim t...
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Lilacs dying? #880524
Asked August 07, 2024, 11:39 AM EDT
The leaves on my lilac bushes have already turned brown and dropped. Same is true at my neighbor's house. Is it the heat? Is it a disease? If I trim them at this time of year, will they be ok next year?
Hennepin 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.
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
It is certainly ok to prune out dead branches, but be sure the branch is dead (scrape some bark off with a fingernail to see if there is green underneath).
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
It is certainly ok to prune out dead branches, but be sure the branch is dead (scrape some bark off with a fingernail to see if there is green underneath).
