Knowledgebase
What is shriveling the leaves on these bushes? #867990
Asked May 11, 2024, 11:42 AM EDT
Several of our bushes have leaves that are curling up. It's on a Korean Spice Viburnum, a french lilac, and this morning I found it on one of our hydrangeas. I'll post pictures. What is it, and what do we do to stop or eliminate it?
Thank you.
Well, it wouldn't let me upload all the pictures, and I can't tell which ones they are. Let me know if you can't see it.
Kent County Michigan
Expert Response
How long ago did these symptoms appear? Have you applied any fertilizers or herbicides around these plants, or on your lawn nearby? Have you had a soil test recently? If you uncurl the leaves and look on the underside, do you see any damage or insects? Does this affect leaves on all parts of the plant, mainly the new growth, or only older growth?
On May 13, 2024, at 10:50 AM, Ask Extension <<personal data hidden>> wrote:
Hello Janet:
I’m sorry to hear about your Viburnum. Koreanspice Viburnum (Viburnum carlesii) are generally problem free although they may get powdery mildew. Read more here: https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=279002&isprofile=1&basic=Viburnum%20carlesii
Lilacs are susceptible to many diseases. Read more here: https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=282932
I wonder if the environment has changed in the last two years. Was there construction that could have affected the roots of the shrub? Has it received the same amount of water as in previous years? Have you seen any leaf spot or mildew? Have there been herbicides sprayed in the area? Had the shrub leafed out and then be hit by a frost? If so, the leaves will recover if it is properly watered. If the shrub has been under stress for the last two years, it may show signs of decline. It is possible that the lilac has powdery mildew. It has shown up on other shrubs that are susceptible to it. Read about powdery mildew here: https://extension.umn.edu/plant-diseases/powdery-mildew-flower-garden
It would appear that the leaves of the hydrangea have been rolled into cups caused by the hydrangea leaftier or leaf roller moth. Read more here: https://bygl.osu.edu/node/1979
The way to get rid of them is to pinch off the pockets or open them up and squish the larva inside. They will not kill the plant but there will be fewer blooms than expected.
Unfortunately, it is difficult to diagnose the problem from the pictures. In order for a definitive diagnosis, you can submit a picture and sample to MSU Extension’s Plant and Pest Diagnostic Lab at: https://www.canr.msu.edu/pestid/
Thank you for contacting Ask Extension.
