Liliac bush - Ask Extension
Hi!
I planted two lilac bush at the same time maybe about 8-10 years ago. The last two years the one has not been looking good (not a lot of leaves) ...
Knowledgebase
Liliac bush #871807
Asked June 05, 2024, 7:37 PM EDT
Hi!
I planted two lilac bush at the same time maybe about 8-10 years ago. The last two years the one has not been looking good (not a lot of leaves) while the other one right across the sidewalk from it looks fine. Every late summer or fall they both get a mildew on their leaves. The one pic is the lilac bush that looks fine (3rd pic) and the other two are the lilac bush that looks sickly (first pic). There is a some growth on the bottom that look okay (second pic). Thanks for your help!
Cathy
Denver County Colorado
Expert Response
Cathy,
Other than the powdery mildew, which seems to be affecting both the healthy and the failing lilac, are you noticing anything other than fewer leaves. are leaves coming out then browning and falling off? are the branches and twigs woody, dry and dead? any insect activity noted? Have trees shaded this lilac more that the healthy one?
The powdery mildew is rarely a cause of shrub failure, but may be a sign that the lilac is not getting enough sun.
Is this bush shaded more that the other? Any runoff from sidewalk salt or other chemicals that might affect one shrub and not the other?
Have you tried pruning it back and seeing if it comes back stronger? here is a link to how to do rejuvenation pruning. Recommended to do this in the winter.
https://ask2.extension.org/scp/tickets.php?id=871807
https://planttalk.colostate.edu/topics/trees-shrubs-vines/1729-renewing-shrubs/
Here are some other lilac care resources:
https://yardandgarden.extension.iastate.edu/how-to/how-manage-potential-problems-growing-lilacs
There are bacterial and other fungal diseases that harm lilacs, but they usually affect leaves.
https://www.purduelandscapereport.org/article/lamentable-lilac-leaf-diseases/
I hope these resources will help you manage your lilac.
Other than the powdery mildew, which seems to be affecting both the healthy and the failing lilac, are you noticing anything other than fewer leaves. are leaves coming out then browning and falling off? are the branches and twigs woody, dry and dead? any insect activity noted? Have trees shaded this lilac more that the healthy one?
The powdery mildew is rarely a cause of shrub failure, but may be a sign that the lilac is not getting enough sun.
Is this bush shaded more that the other? Any runoff from sidewalk salt or other chemicals that might affect one shrub and not the other?
Have you tried pruning it back and seeing if it comes back stronger? here is a link to how to do rejuvenation pruning. Recommended to do this in the winter.
https://ask2.extension.org/scp/tickets.php?id=871807
https://planttalk.colostate.edu/topics/trees-shrubs-vines/1729-renewing-shrubs/
Here are some other lilac care resources:
https://yardandgarden.extension.iastate.edu/how-to/how-manage-potential-problems-growing-lilacs
There are bacterial and other fungal diseases that harm lilacs, but they usually affect leaves.
https://www.purduelandscapereport.org/article/lamentable-lilac-leaf-diseases/
I hope these resources will help you manage your lilac.
