Hi Danielle, 

We do not think this looks like verticillium wilt, but  you can prune off a dead branch and check near the base of it for staining. Some grafted ornamental trees are grafted on both the bottom and top - it is possible that part of the top graft failed. 

Can you tell us about your watering routine? Does a downspout drain to this area? We do see something in the bottom corner of one of the photos that looks like landscape fabric - is there a barrier under the bark mulch?

If you are able, could you send us some more photos of the base of the tree and the area in general so we can take a look at the environmental conditions that may be impacting the tree?

Jamie

Good afternoon - I think I replied in a separate e-mail, which may not have been linked to this existing string.  I've also included additional pictures.

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Thank you so much for your response! This is sounding optimistic, which is exciting.

We do not do any extra watering of the Japanese maple. We do not have a downspout directly "watering" the maple; however, in the first additional picture (4745) we have a downspout that releases water kind of in front of the second small boxwood from the right. There is also another downspout a bit to the right of the holly (on the left side of the house) but not directly in line with the maple.  So-the Maple is not getting saturated with water.  The maple is in sun all day.

I did clear the mulch away from the tree and do not see fabric so we may be ok there.

Hope these additional pictures help.  Take care and you all are great! This is so helpful.

First additional picture posted.

Second additional picture posted.

Third additional picture posted.

One more thing - we get some pretty strong winds and they cut across the front yard hitting the Japanese Maple.  Thanks again for the continued insight.  

Hi Danielle!

Thanks for the additional photos and details. The new photos clarify the positioning of your downspouts, and we no longer think that is a possibility. Neither do we suspect that a pest caused the damage. 

A theory we have is that the landscape lighting may have interfered with the tree's ability to prepare for dormancy on time, which may have made it susceptible to winter damage. There have been studies that show this effect on some street trees that are under street lighting. The resulting winter damage may have allowed for a fungi or pathogen to enter and cause the dieback you see. The lighting appears to be focused on the part of the tree that died back, which would make sense as the damage is localized to that area. Again, this is a theory! You could experiment with moving the lighting to see if it reoccurs this year. Plants start preparing for dormancy weeks before the temperatures dip to freezing, so the damage may have been done when it was still warm outside. 

The dead branch will not recover, so we recommend pruning it out. Check the base of this branch for staining so we can rule out verticillium wilt. The suckering growth is normal for Japanese Maples and you can also prune this out. If the suckering doubles, we would consider this to be a symptom that the tree is suffering from additional stress, so continue to monitor the tree for changes. 

Jamie

Good afternoon - Thank you for all the insight!  We did trim back the branches and am attaching pictures of the base of one of the branches.  I am not sure if this is the "staining" that you were referring to.

We had a soil sample done and our soil is generally ok (a little high in potassium).  The tree people were suggesting verticillium wilt but not sure what that is based on.

If you think that the staining shown aligns with verticillium wilt, I'd be interested in knowing.  If it is, I realize our poor maple is doomed.  Are we able to replant other things in that location just not a Japanese Maple?

Thank you so much! I have been telling several people about your service...it is awesome! Danielle

Image 1 - staining?

Image 2 - staining?

Hi Danielle, 

I had our plant pathologist take a look and he confirmed it is not verticillium wilt, but it is likely Botryosphaeria canker, another common disease caused by a fungal pathogen. Prune off any of the remaining infected areas. 

Because the tree seems to be stressed in this location, it might continue to decline. If you choose to replant, Botryosphaeria doesn't linger in the soil, so you can plant something else without a problem. I suggest a tree or shrub that favors full sun, as Japanese maple are similar to dogwoods in that they prefer to be understory trees with dappled sun. 

Jamie

Thank you so much, Jamie!  I appreciate all the feedback and the confirmation.  I will see if I can move our Japanese Maple to a more suitable location - I want the plant to thrive :-).  Take care.

My pleasure! You can write us at Ask Extension any time with your questions.

Jamie