Diagnostic advice for a Japanese Maple
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JeanneK
Location: Oregon, Greater Portland Metro
Posted: Oct-05-2004 at 9:33am
I need some diagnostic advice for one of my japanese maples. I have two JM's in my front yard, a Southern Exposure. They must have been planted at least 30 years ago. They are now about 15 ft. tall. I noticed that they seem to get some crispy leaves during our dry summers. This year, one appears to be healthy and still has yellow/green leaves. The other lost a part of a branch this winter and the other part appears to have died now. The leaves on this tree have started to change to orange/red, normal color for this tree. I tried to give it more water this summer in hopes of helping it along. Also, I built a 2-3 ft berm in this area two years ago, about 4-5 ft from the trunk of this tree. I have tried to ease the level of berm to be even with the level of the soil around the JM. The soil around the trunk has not been increased or move around. The berm houses native plants and has a soaker hose that gets turned on every couple of weeks in dry weather for a couple of hours.
So, do you think I have verticillium wilt in this tree or is the berm impacting the tree? The dead branch is the one over the berm. Is it getting too much water? I will check the dead branch for blackening of the cambium layer. I don't want to loose the tree but I am afraid it is a goner.
Jeanne
Wanda
Location: Puget Sound corridor
Posted: Oct-05-2004 at 10:34am
Oh, I hope you're wrong and it's not a goner. It is just sickening to think of losing such a wonderful tree. Maybe it doesn't like the root competition of the other plants - you usually don't see them underplanted with much. I hope someone else chimes in with some real advice for you.
-Wanda
JeanneK
Location: Oregon, Greater Portland Metro
Posted: Oct-05-2004 at 11:55am
Hi Wanda. Thanks for your sympathy! The JM lives with an old arbor vitae but it grew up with it. I tried not to plant anything to close to the trunk. The closest plant is a small twinflower, about 4ft away, somewhat under the leaves of the dead branch. The twinflower was a bareroot when I planted it in early March.
I have looked into VW more and realize that the vine maple I planted two years ago in this berm is experiencing similar symptoms. When I get home, I'll have to check the leaves of both plants for the yellowing/streaked foliage. Guess I need to take a branch in for confirmation.
I'll wait until next year to see if both maples pull through.
Jeanne
JeanneK
Location: Oregon, Greater Portland Metro
Posted: Oct-07-2004 at 2:06pm
Well, I cut off a small branch. I couldn't really see any streaks across the cambium layer that would indicate VW so I guess I will have to take it in to the extension office.
Lisa, MD, any body out there have any advice?
Jeanne
mdvaden
Location: Oregon, Western
Posted: Oct-07-2004 at 6:48pm
Interestingly, I heard the "Garden Doctor" repeat that there is no solution for verticillium wilt - BUT... - he did, this last weekend, mention compost tea or soil soup as an effort with possibilities.
Maybe you have the wilt, maybe not.
But I was going to chime in about fill soil. The potential harm is not from adding soil around tree trunks. The potential harm is from adding soil over the roots and root zone, which can extend a ways out at times.
Do you think you added soil over the root system?
M.D. Vaden
JeanneK
Location: Oregon, Greater Portland Metro
Posted: Oct-08-2004 at 9:01am
There is additional 2ft of soil under a portion of one of the branches. I don't know how far out the root system goes. But it does seem suspect that the branch with the most additional soil under is dying.
Does the additional soil compact the soil too much? This area was covered with grass prior to the berm.
Jeanne
Lisa A
Location: Oregon, Greater Portland Metro
Posted: Oct-08-2004 at 12:58pm
IIRC, additional soil over roots interfers with oxygen absorption in the roots. I think as little as a few inches will interfer with this. General rule of thumb - roots extend as far out as a tree is tall. This might be the problem, which is an easier fix than verticilium wilt.
Gardening for the Homebrewer: Grow and Process Plants for Making Beer, Wine, Gruit, Cider, Perry, and More
By co-authors Debbie Teashon (Rainy Side Gardeners) and Wendy Tweton