Japanese Lilac - Ask Extension
Diameter of 13”, height of 18’. One large limb has leaves turned brown and curled. The leaves which have not turned yet show a wilting appearance,...
Knowledgebase
Japanese Lilac #909730
Asked July 14, 2025, 10:43 AM EDT
Diameter of 13”, height of 18’. One large limb has leaves turned brown and curled. The leaves which have not turned yet show a wilting appearance, something like a Shepherd’s Crook which I have read about. Nearby limbs and leaves seem to be showing the start of a wilting look. Can this condition be alleviated? I have taken down the worst limb.
Hennepin County Minnesota
Expert Response
Is this a Japanese Tree Lilac? Are all the wilting leaves on one side of the tree? If so, it may be suffering from herbicidal drift. Have you or your neighbors near the tree have sprayed for insects, weeds, etc.
Those branches may die, but the rest of the will be okay.
Other possible causes are:
Lilac Borer, a pest that tunnels into branches, causing wilting, especially in drought-stressed trees. Severely infested branches may break off. Remove and destroy infested branches. https://yardandgarden.extension.iastate.edu/encyclopedia/lilacash-borer
Verticillium Wilt is a fungal disease that can cause wilting and premature leaf drop, potentially killing branches. Verticillium wilt can be difficult to treat, but proper fertilization and stress reduction can help. See the picture in this web page tohelp check for under bark damage.
https://hort.extension.wisc.edu/articles/verticillium-wilt-of-trees-and-shrubs/
Bacterial Blight can cause wilting and blackening of young shoots and leaves, especially during wet weather. Remove infected branches and avoid over-fertilizing, especially with nitrogen.
https://hort.extension.wisc.edu/articles/bacterial-blight/
You can submit a sample to the Plant Disease Clinic for a fee. https://pdc.umn.edu/
Those branches may die, but the rest of the will be okay.
Other possible causes are:
Lilac Borer, a pest that tunnels into branches, causing wilting, especially in drought-stressed trees. Severely infested branches may break off. Remove and destroy infested branches. https://yardandgarden.extension.iastate.edu/encyclopedia/lilacash-borer
Verticillium Wilt is a fungal disease that can cause wilting and premature leaf drop, potentially killing branches. Verticillium wilt can be difficult to treat, but proper fertilization and stress reduction can help. See the picture in this web page tohelp check for under bark damage.
https://hort.extension.wisc.edu/articles/verticillium-wilt-of-trees-and-shrubs/
Bacterial Blight can cause wilting and blackening of young shoots and leaves, especially during wet weather. Remove infected branches and avoid over-fertilizing, especially with nitrogen.
https://hort.extension.wisc.edu/articles/bacterial-blight/
You can submit a sample to the Plant Disease Clinic for a fee. https://pdc.umn.edu/
