Lilac bushes - Ask Extension
I have in my yard some lilac bushes that are at least 25 years old, probably much older. I say this as a guess from what my older neighbors have said ...
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Lilac bushes #878370
Asked July 23, 2024, 7:50 AM EDT
I have in my yard some lilac bushes that are at least 25 years old, probably much older. I say this as a guess from what my older neighbors have said and the year the house was built, 1964. We have been care taker of these beautiful sturdy plants for the last 15 years. They are unfortunately under a power line and need us to trim them every few years for safety which we haven’t Done in a couple of years. We have always trimmed around bloom time and never had any problems and they’ve looked beautiful for years. This year they’re looking sick. About two weeks ago the leaves started to turn brown a bit and now almost the entire shrub is brown and I’m worried we’re going to loose them. DO you have any ideas what is wrong with our beautiful lilacs and what we can do to save them?
Dakota County Minnesota
Expert Response
Thank you for writing.
This is lilac blight of which we are seeing a lot this year.
https://www.purduelandscapereport.org/article/lamentable-lilac-leaf-diseases/#:~:text=The%20Septoria%20and,prevent%20further%20defoliation
Your plants are stressed by the heat and rain BUT they are also stressed by a lack of pruning over a long time.
Remove dead stems now.
Clean fallen leaves now and in the fall.
Leave the rest of this until winter.
So the rehabilitation of this patch should consist of renewal pruning by removing 1 /3 of the oldest, thickest stems to the ground to open up the shrub.
Repeat this for two years. Allow the smaller shoots to grow up, essentially creating an all new lilac.
https://holdenfg.org/blog/rejuvenation-pruning-of-lilac-bushes/
This is lilac blight of which we are seeing a lot this year.
https://www.purduelandscapereport.org/article/lamentable-lilac-leaf-diseases/#:~:text=The%20Septoria%20and,prevent%20further%20defoliation
Your plants are stressed by the heat and rain BUT they are also stressed by a lack of pruning over a long time.
Remove dead stems now.
Clean fallen leaves now and in the fall.
Leave the rest of this until winter.
So the rehabilitation of this patch should consist of renewal pruning by removing 1 /3 of the oldest, thickest stems to the ground to open up the shrub.
Repeat this for two years. Allow the smaller shoots to grow up, essentially creating an all new lilac.
https://holdenfg.org/blog/rejuvenation-pruning-of-lilac-bushes/
