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I have a Japanese Lilac Tree that was fine 2 weeks ago now there is 2 dead branches and 1 that is starting to die.

They are not isolated and are random, with the first near the base of the canopy one one side, then another on the other side. The most recent branch showing symptoms is in the upper 3rd of the canopy.

I can't figure out what to do with this exactly other than remove the branches.

Can someone help me save this one?

Thank you

enter image description here

M H
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user31157
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    How long have you had the plant? Where are you in the world and is it in a pot or in the ground? – Bamboo Jul 27 '20 at 18:07
  • Well written question & good illustration; also, an overall illustration, and one of branch ends & failing leaves could be helpful. When trimming off to good wood, maybe dip the pruner in some 1/10 bleach solution before Each prune, prune, & then seal it. – M H Jul 27 '20 at 18:30
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    It's over 15 y/o and we are in Minnesota USA. Tree is in ground. Mulch has been piled up by previous landscapers. – user31157 Jul 28 '20 at 04:49
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    I was unable to add the other 3 photos (not used to this upload style forum) however it looks a lot like a maple tree with verticullum wilt although more random. I'll try in the morning to upload the other. Thank you both for you fast responses! – user31157 Jul 28 '20 at 04:52
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    Also, the dead shoots that leaves are most wilted are almost black with sooty mold. – user31157 Jul 28 '20 at 04:53
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    Basically the spots on the green leaves are the first symptoms from what I gathered. The blurry spots gradually increase in size as the leaves begin to wilt eventually turning olive then brown to black.. There is one branch picture I'll upload showing some lesions. May not be related, possible. – user31157 Jul 28 '20 at 04:57
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    Trace the branches down the trunk, see if there is an injury on the trunck. – Polypipe Wrangler Jul 28 '20 at 05:32
  • Very helpful additional information! – M H Jul 28 '20 at 15:17
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    You mention mulch piled up - has it been piled up around the base of the trunk, in contact with it? – Bamboo Jul 28 '20 at 15:20
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    Mulch has been built up over the years but not as bad as some other trees. I suspect this was a stressor that added to overall stresses. So many people in my area do the "volcano" which is fine, I tell them, as long as there is a gap between the mulch and the trunk. I have thought as a good rule of thumb that once the mulch is over the trunk flare, it's time to remove and replenish. – user31157 Jul 29 '20 at 01:31
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    Thank you everyone for your input! I will give the Vert test a go and see what the results are. – user31157 Jul 29 '20 at 01:36

2 Answers2

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Your Japanese Lilac may be suffering from Bacterial Lilac Blight, based on the clear illustration & additional description, and your Lilac may be saveable!

Some Lilacs survive Lilac Blight, especially with care. Blight can get into a Lilac through open abrasions or from insects etc, & moves through the tissues in the plant, and progess can be very rapid. Sometimes Blight will take an entire Lilac, other times several branches. Insects can very quickly spread it from branch to branch, and from plant to plant, so control of insects that can spread it is very important.

To reduce occurrence & spread of Lilac Blight includes: prompt removal of all affected branches & leaves and other debris, keeping the leaves dryer when watering, and thorough removal of insects which may spread it. One insect can quickly spread Blight to several branches.

When trimming off affected branches, trimming back 60-100 cm from where there's moist tissue can help if Blight hasn't already spread through the branch; typically, an affected branch may entirely fail. Importantly, when trimming back or removing entire branches, dip the pruner in a 1/10 bleach solution before and after Each prune, and Immediately seal Each prune! And avoid any trimming off if it's raining or rain is imminent, because rain could spread it.

Removing the mulch from around the Lilac would be a good idea, because mulch retains moisture, and because mulch can attract & conceal insects which spread Blight.

Although some suggest that there isn't any treatment for Blight other than carefully trimming away affected branches & Immediately sealing them before it spreads to healthy tissue, and that the entire Lilac will fail, Some have had good results using copper eradicants: so perhaps check what may be available in your area, as it could be important & helpful!

Keeping watch for any newly affected leaves or branches and immediately carefully removing them is very important because Blight can progess so quickly. Hopefully your Lilac can be saved!

M H
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  • I'm not convinced it's lilac blight - seems more like verticillium. Either way, the lilac is pretty much toast. Here's more info on blight from one of the best horticultural programs in the US: https://hortnews.extension.iastate.edu/lilac-bacterial-blight. It's important to note if it's verticillium, as that can also infect viburnums and redbuds. – Jurp Jul 28 '20 at 22:45
  • Thank you for your comment; have seen their site previously, in fact they also suggest dipping a pruner in a bleach solution, but the y don't offer much in the way of diagnostics; also, it could be something which isn't well documented; the objective is to save the Lilac if possible, and many such things progress so rapidly that providing the Asker with as much information as possible may help save the lilac. And useful preventive note re other possible affectees; additional illustrations being unavailable, suggestions to most safely remove affected branches seems to be universally sound. – M H Jul 29 '20 at 03:58
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This could be verticillium wilt, which causes sudden death of individual branches. Here's some info. It's important that you read the link, because it contains a diagnostic test that you can use to determine whether your lilac does indeed suffer from a verticillium infection. If your lilac fails the test (no streaking on the twigs), then your plant may indeed have lilac blight or something else.

However, it may be just a weird one-year event...

Last year, two of my four lilacs suffered branch dieback, one of them severely. I suspected verticillium and performed the test on a few branches. They were clean, and I was confused. This spring, I spoke with a neighbor who had a lilac tree that had had the same problems. We compared notes and discovered that both sets of lilacs had had a fantastic bloom in 2019. This year, all of the lilacs are fine. I pruned out the deadwood from 2019 and the plants are doing okay. I have no explanation for this, but am happy that my lilacs aren't dying. Maybe you, too, will be lucky like this. I hope so!

Jurp
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