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deformed leaves on panicle hydrangeas #806538

Asked August 16, 2022, 11:59 AM EDT

I am noticing deformed leaves on my panicle hydrangeas in all different areas of my landscape. I do not use herbicides. They are on the new growth and where the flowers should be growing. What is causing this and what can I do to get rid of it or keep it from spreading to other bushes?

Leelanau County Michigan

Expert Response

Kim,

Is it only the hydrangeas in the area that have these tiny leaves? Do other plants look ok?

Has there been any excess water in this area? 
Erin Hill, PhD Replied August 22, 2022, 3:22 PM EDT

It is only on hydrangeas and the other plants look okay. We have not had excess water and we have irrigation so they are all on drip. The ones right next to the few that have this going on are completely normal. Thanks for your help.

The Question Asker Replied August 22, 2022, 3:37 PM EDT
I have an email out to my collegues (entomologist and pathologist) to see if they have seen anything like this before. To my knowledge there are no viruses that would cause this in panicle hydrangea. I will let you know if they come up with something.

Herbicides can travel some distance under the right conditions. Do you suspect any of your neighboring areas may have applied anything to lawn areas? Also, some herbicides cause damage the season after application. Am I correct in assuming that there has never been any herbicide use in this areas? 

Another suspicion I am following up on is nutrient imbalance, but it seems a bit far fetched to cause these particular symptoms.
Erin Hill, PhD Replied August 22, 2022, 3:55 PM EDT

I live in a wooded wetland area across from Big Glen Lake, an inland lake near Glen Arbor. We have a lawn but have never used herbicides because it is heavily frowned upon in our area, so close to the lake and wetlands that feed into the lake. I don't think it's a nutrient imbalance because of the close proximity to the other hydrangeas who are fine. I use Hollytone every spring on all my hydrangeas and then nothing else the rest of the year.  I am also a gardener for quite a few other homes in my area, same lake etc. and I have seen this on panicle hydrangeas this year at 3 other homes. Do you think it could have spread from my pruning clippers? I wipe them with clorox wipes after each garden, but maybe that is not enough? 

The Question Asker Replied August 22, 2022, 4:03 PM EDT
My colleagues have not seen symptoms similar to this caused by insects/arthropods or pathogens. 

One did wonder if you have spread any fresh woodchips or mulch in the area. Sometimes inputs such as these can be the source of herbicide exposure. 
Erin Hill, PhD Replied August 24, 2022, 3:31 PM EDT

In my yard we have not spread fresh mulch or chips this year but in a couple of the other yards there has been mulch spread this year. Do you think this is something that can be spread from yard to yard via clippers?

The Question Asker Replied August 25, 2022, 9:07 AM EDT
That doesn't seem likely. I am kind of at a loss for what is happening in this instance without a source of herbicide exposure. 

You could submit a physical sample to our diagnostic lab (https://www.canr.msu.edu/pestid/), but if it doesn't turn out to be a pathogen or an arthropod/insect issue we may not have a conclusive answer.

Please let me know if you have questions.
Erin Hill, PhD Replied August 29, 2022, 4:53 PM EDT

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