Zelkova - Ask Extension
I have a 10-year-old Zelkove that began showing leaf wilt in one area last spring. Now 90% of the tree is involved. The spring leaves appear normal ...
Knowledgebase
Zelkova #752748
Asked May 28, 2021, 3:32 PM EDT
I have a 10-year-old Zelkove that began showing leaf wilt in one area last spring. Now 90% of the tree is involved. The spring leaves appear normal but then the terminal edges turn brown. Drought was suggested but the tree is in an area that is fairly wet. I don’t see any obvious bugs. The first photo is the top of the branch. The second is the underside of the same branch. The third is just to show what I assume is algae in case that is significant
Multnomah County Oregon
Expert Response
Zelkova are generally pest and disease free trees. Please send a couple more photos showing the whole tree from a distance, and one showing the trunk area where it reaches to soil.
Did you plant the tree? Do you know for sure if all root baskets, twine, and other material like burlap was removed at planting time? Any root/planting photos from that time? (Circling roots can “strangle” a tree years after planting.)
How do you care for the tree regarding fertilizer, irrigation or weed control nearby?
Root problems or leaf blight are possible issues, and we look forward to troubleshooting this with you. The yellow lichen is not a problem for tree health.
Here’s basic tree information to share.
First of all, thank you for your prompt response!
I tried to get a photo of the Zelkova from a distance. However, our house is close-in in Portland with surrounding houses, buildings and vegetation so the photos are les than adequate.
As you can see, the trunk is surrounded by plants. I hope you can get an idea from what I sent.
Also, we have always contended with sinking of an area of our patio that requires we take up the pavers and pack the hole with dirt. This hole is about 4 feet from the trunk. I include this info on the off chance it is useful.
I included a photo of the yard to give you a sense of what is around the tree. The garden is well tended and mulched every year. But I have not fertilized the tree. There is an irrigation system. As I mentioned, the backyard is fairly soggy in the winter.
Finally, i know the tree was planted properly without burlap and at appropriate depth.
Thank you so much for your help!
Patricia
Jacki is right about there being few problems reported on these trees. There are some issues in the nursery but not once in the landscape. Most of the problems are found in Japan but there are two reported in California that concern me.
You images are showing us a branch with many leaves that have marginal and tip necrosis. This is due to a water imbalance where water from roots is not getting to the leaves and/or there is too little water coming into the leaves to keep up with transpiration. The other images show a normal tree without major wounds or things that might contribute to these symptoms.
Armillaria root rot was reported in CA but I don't think that is what is going on here. It could be related to your minor sink hole but the next issue is more important.
The fungus Ophiostoma ulmi was also reported in CA. That has the common name of Dutch Elm Disease. Now before we get too excited, Zelkova is considered resistant. But that does not mean it might not get the disease. The marginal leaf burn is consistent with this disease. I would also look for vascular streaking in the xylem. You read up on this disease here but I would be more concerned if it were an American elm:
https://pnwhandbooks.org/plantdisease/host-disease/elm-ulmus-spp-dutch-elm-disease
The only way to know for certain is to send a sample into the the OSU Plant Clinic (and I highly recommend it):
https://bpp.oregonstate.edu/plant-clinic
I have a few other places to look for information and will get back to you if I find anything else.
You images are showing us a branch with many leaves that have marginal and tip necrosis. This is due to a water imbalance where water from roots is not getting to the leaves and/or there is too little water coming into the leaves to keep up with transpiration. The other images show a normal tree without major wounds or things that might contribute to these symptoms.
Armillaria root rot was reported in CA but I don't think that is what is going on here. It could be related to your minor sink hole but the next issue is more important.
The fungus Ophiostoma ulmi was also reported in CA. That has the common name of Dutch Elm Disease. Now before we get too excited, Zelkova is considered resistant. But that does not mean it might not get the disease. The marginal leaf burn is consistent with this disease. I would also look for vascular streaking in the xylem. You read up on this disease here but I would be more concerned if it were an American elm:
https://pnwhandbooks.org/plantdisease/host-disease/elm-ulmus-spp-dutch-elm-disease
The only way to know for certain is to send a sample into the the OSU Plant Clinic (and I highly recommend it):
https://bpp.oregonstate.edu/plant-clinic
I have a few other places to look for information and will get back to you if I find anything else.
Jay:
Thanks for this information!
I had looked at the twigs previously because I was thinking this might be Verticillium even though Zelkova are resistant. We lost a Japanese maple about 4 years ago that was located about 50 feet from this tree. It wasn’t diagnosed in a lab but it had many of the verticillium characteristics. So the central twig on the Zelkova was discolored but there wasn’t discoloration peripherally.
Also, we live in an old neighborhood in PDX that has lost many old elm trees in recent years. So maybe Dutch elm disease is correct. I will send a sample to the lab!
Thanks again!
Patricia
Vert is one of the things I thought of as well right away. That is why I searched the fungal reports and it does not come up. DED does. Both are Xylem limited but the key is where you see the streaking. With DED it will be in the affected branch but as you go down you will transition from diseased into healthy tissue. The opposite will occur with Vert since it starts in the roots. Diseased vascular tissue will be below. The Plant Clinic will be able to determine which it might be.
I was able to search a different data base we have. There do seem to be some stem cankers that occur after cold injury events. This may be lower on my list that DED. Did you have any ice storm damage back in FEB on this tree?
Jay:
There was no obvious damage to the Zelkova. Also, the first signs occurred last spring/summer so before the ice storm.
OK then, we will wait and see what the Plant Clinic report tells us.
ATTN: Dr. Pscheidt Re: #0022679
Dr. Pscheidt:
I am forwarding the plant pathology lab results concerning the Zelkova.
I suppose it is good news that it is not DED.
I am wondering what the next step might be. We have now filled in the sink hole hoping by some chance that would remedy the problem; however, judging from previous experience, it will recur with time. Any other ideas?
I am not sure the heat wave is doing the poor tree any favors. And perhaps the diagnosis is simply climate change. We need to do something about that!!!!
Thanks,
Patricia
Plant Specimen Diagnostic Report # 2021-849 Zelkova
Inbox
OK then, we will wait and see what the Plant Clinic report tells us.
Good to know we don't have Dutch Elm here. As the Plant Clinic also noted there must be something going on at or below ground. I suspect you might have seen more damage after this very hot weekend?
Since the only other thing to note is the sink hole, that might be the issue with the tree. Sink holes like this could be an indication of a damaged drain pipe. An expensive fix if you should go after it. You might see about getting someone that knows about these things to visit - the sink hole that is, not the tree.
At this point I am not too worried about the tree. Lets wait and see if there is more damage as time goes on. In the mean time, I would investigate the sink hole a little more.
Since the only other thing to note is the sink hole, that might be the issue with the tree. Sink holes like this could be an indication of a damaged drain pipe. An expensive fix if you should go after it. You might see about getting someone that knows about these things to visit - the sink hole that is, not the tree.
At this point I am not too worried about the tree. Lets wait and see if there is more damage as time goes on. In the mean time, I would investigate the sink hole a little more.
