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Lilacs (Miss Kim) sick #874930

Asked June 27, 2024, 10:15 AM EDT

Hello! My 'Miss Kim" lilacs are not well. They were robust for 15 years but not this year. Most of the limbs look dead but when examined I see they have green, flexible centers. Last year I watered them more than usual because of the drought. I know they've been stressed because of 3 dry years but could this be from over watering? More concerning...does this look like 'Witches Broom' disease? Mites? Please advise.

Dakota County Minnesota

Expert Response

I agree that your lilacs do  not look good. I can’t diagnose this for certain but from your photos it does look like witches broom. 

If that is the case, you can prune out the affected branches but these look pretty far gone. You may want to prune them to the ground and see how they come back next year. If this continues, you will want to dig and remove all of them. If it is witches broom they will weaken and eventually die. 

Lilacs are an alternate host for Ash yellows. if you have ash trees around this could be a possibility. 

Sorry for the bad news.

https://extension.psu.edu/lilac-diseases

https://ag.umass.edu/landscape/fact-sheets/ash-yellows

https://pddc.wisc.edu/2020/08/10/august-2020-green-grow-the-lilacs-not/

Deb Reierson Replied June 27, 2024, 10:26 PM EDT
Hello and thank you for the information,
I will prune the lilacs back and see how it goes.  Should I do the pruning now or wait until fall when things become dormant?
Thank you,
Joan
From: ask=<personal data hidden> <ask=<personal data hidden>> on behalf of Ask Extension <<personal data hidden>>
Sent: Thursday, June 27, 2024 9:26 PM
To: Joan Gonzalez <<personal data hidden>>
Subject: Re: Lilacs (Miss Kim) sick (#0144848)
 
The Question Asker Replied June 28, 2024, 5:51 PM EDT

Pruning them now is fine. Usually you would prune lilacs right after bloom. Even if they come back looking healthy you may not get blooms next year.

Deb Reierson Replied June 29, 2024, 8:27 AM EDT

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