Question
Hi,
I have a red coral bark japanese maple that was planted last year. It is in full sun. Recently, I have noticed the upper branches turning from bright red to a dark brownish or black color. The discolored branches also seem to be drying out. Some of the lower branches are still healthy and have started to sprout leaves. My area has gotten a lot of rain lately, basically everyday for the last month. Could you please tell me what could be wrong and how to fix it. This is one of my favorite trees.

Thank You

Answer
Hi Stephanie:
Wonderful trees!

The brownish black discoloration can be an indication of one of two things. There maybe a disease organism on the branches that is killing tissue from the tips downward or from lateral branch stubs OR the tips are dying as a result of root/soil related stress.

Since it was planted last year, I would not attempt to dig up tree to make any changes, but the best thing to do is to remove the discolored areas of the branches by pruning those branches or parts of branches out. Locate where the brown/black area stops and normal branch color starts, then go back into the normal wood to make your cut.  This will help ensure that you get all of the discolored portions out.  Be sure to do this pruning on a dry day when no rain is expected for a couple of days.  As a precaution, you can spray your pruners with rubbing alcohol each time you make a cut. Allow the alcohol to dry off before you cut the next branch.

If you have had a lot of rain, cut back on watering your tree and just watch to see if additional branches discolor. Try to keep any new ones pruned also.

Regards
Steve