Lilac bush is browning quickly!

Asked July 29, 2020, 2:46 PM EDT

Do you think this is a case of bacterial blight? The entire shrub's leaves are brown and curling but the leaf deterioration began with brown/yellow spots and burn curling on the edges of the leaf. None of the other lilacs nearly have shown signs yet. Do you think it will spread and what is your recommendation? With gratitude for your wisdom! Donna von Lehe Stillwater, MN

Washington County Minnesota

1 Response

Thanks for the question.

Yours is one of many that we have recently received regarding the browning of lilac leaves. Bacterial blight is certainly a possibility and maybe the most likely. If it is blight and to protect your other lilacs, you may want to prune everything on this one plant down to within a foot or more from the ground. Discard all material in the thrash. Although it may take a few years, the lilac should recover. See:

https://hortnews.extension.iastate.edu/lilac-bacterial-blight

https://apps.extension.umn.edu/garden/diagnose/plant/deciduous/lilac/leavesbrownwilted.html

As Master Gardeners we have been discussing what might be going on since what you are observing has been seen by many other gardeners in the Metro Area and surrounding cities. Leaf samples have been submitted to the Plant Disease Clinic of the University of Minnesota for analysis. As these analyses can take some time, it is not clear when we will get results back.

For the time being I would suggest that you deal with your lilac as if it does have bacterial blight.

Good Luck!!