Unhappy/Sick Acer shirasawanum Sensu (in container)
I have a Sensu, which I bought in late January or early February. Early this spring, I bare rooted, did some minor root pruning/correction (ie removed circling and "j" roots) and potted into a 20" cedar container in the 1:1:1 gritty mix from the container forum.
For several months the tree seemed to be very healthy.
As time went by, I noticed the leaves seemed droopy during the day, but seemed to perk up at night. I wasn't sure if this was related to temperature change from night to day (although it has been a very cool spring, even for western WA), or possibly due to the roots not being able to keep up with transpiration during daylight hours. So my first "experiment" to see if I could make things better was to thin the tree some to reduce the amount of transpiration. This seemed to work for a while, but eventually the droopiness came back and eventually got worse.
Over the course of several months I've done things like adjusted watering, adjusted fertilizer amount and timing (been using Foliage Pro in a 1/4 dose on a weekly schedule, but I've adjusted that to the recommended "maintenance" dose), moved into more shade, almost full shade now, and finally in desperation I moved the tree into a 2 gallon nursery container and planted it into the ground.
When I moved the tree (I know this isn't recommended while the tree is in leaf) I noted that the root mass seemed smaller than when I repotted earlier this spring, indicating I may have a problem with root rot or pests.? It has been a very wet spring here, even by our standards, so it's possible this particular root stock didn't like the wetness even in a free draining soil like the 1:1:1 mix. For a note of comparison, I have 5 other trees in the 1:1:1 mix and 5 additional trees in a mix close to the 5:1:1 mix. All of those trees are doing great, even with the cool, wet spring we've had.
Noting the small root mass would be fairly close to the surface in the container, I covered the top with some moss I dug out of the side yard. I also clipped one of the small limbs with only 2 leaves on it and split the limb open to see if I could find any signs of verticulum wilt.
Here's that picture.
Here's a picture of one of the leaves from that limb.
Here's a picture of the tree from today.
As the pictures show, the tree is still quite droopy, but the leaves aren't browning or wilting. The branch I cut open doesn't seem to show any signs of black streaking, so I don't think it's verticulum, but I'm certainly no expert or even all that experienced for that matter.
I have a thread where I've been following the growth of all my maples, including this one, with links and pictures going all the way back to February, if any of that would be helpful in diagnosis.
Any help or advise would be greatly appreciated.