why are my lilac leaves falling off? - Ask Extension
My lilac bush leaves are turning brown and falling off from the bottom up.
Knowledgebase
why are my lilac leaves falling off? #879103
Asked July 28, 2024, 11:45 AM EDT
My lilac bush leaves are turning brown and falling off from the bottom up.
Montcalm County Michigan
Expert Response
Hello Matthew
We have had a large number of questions like yours on lilac this year. Conditions have been ideal( humid, wet, warm) for leaf spot diseases on lilac. It is too late to apply anything to he plant, other than keeping it watered during dry times. Redirect sprinklers, or water early in the day, so leaves are kept dry or will be dried quickly in the sun.
I can't be sure of what is causing the problems, but it does look similar to bacterial blight psuedocercospora leaf spot. There are bulletins below on leaf diseases.
A “rejuvenation pruning" may be helpful next spring after it flowers.
Rake up all fallen debris this fall to minimize overwintering pathogens.
https://extension.oregonstate.edu/news/how-recognize-treat-avoid-lilac-bacterial-blight
https://hnr.k-state.edu/extension/horticulture-resource-center/common-pest-problems/documents/Lilac_Pseudocercospora_Leaf_Spot.pdf
https://lancaster.unl.edu/hort/articles/2005/prunelilacs.shtml
We have had a large number of questions like yours on lilac this year. Conditions have been ideal( humid, wet, warm) for leaf spot diseases on lilac. It is too late to apply anything to he plant, other than keeping it watered during dry times. Redirect sprinklers, or water early in the day, so leaves are kept dry or will be dried quickly in the sun.
I can't be sure of what is causing the problems, but it does look similar to bacterial blight psuedocercospora leaf spot. There are bulletins below on leaf diseases.
A “rejuvenation pruning" may be helpful next spring after it flowers.
Rake up all fallen debris this fall to minimize overwintering pathogens.
https://extension.oregonstate.edu/news/how-recognize-treat-avoid-lilac-bacterial-blight
https://hnr.k-state.edu/extension/horticulture-resource-center/common-pest-problems/documents/Lilac_Pseudocercospora_Leaf_Spot.pdf
https://lancaster.unl.edu/hort/articles/2005/prunelilacs.shtml
Sorry, the pruning link appears to be broken.
Here is another, describing rejuvenation pruning which is done in stages, in late winter.
Here is another, describing rejuvenation pruning which is done in stages, in late winter.
https://lancaster.unl.edu/rejuvenating-older-lilacs
Regards,
Laura
