This 'Kasagiyama' budded out later than all my other Japanese maple and now it's doing this thing.. what is going on here? I went to a very reputable nursery around here and they still couldn't identify it. It's sitting in the shade for most of the day and gets dappled light from 3 - 7/8 The first two pictures are of the problematic top half and the last one is what the bottom half looks like.
Are those spider webs in the first picture? I ask, because one year I had a green spider in my coral tower. It would wrap itself in the leaf for protection during the day and the leaf would later fail. As things progressed, I would have a dead leaf for every day that went by until I killed the spider. Not sure what kind of spider it was but they must not be very common in my area. I have not seen one since and I never had that problem before.
How long have you owned this tree and how long has it been in its present location? If it's been in the same location and done well for years and the site conditions have not changed (drainage, sun exposure/intensity) then look at the bark on the trunk leading up to the second half of the tree for area(s) of dark discoloration. If the tree is new to you or new to the location, I would check to make sure the soil is not staying too moist. I would also check to make sure the top part is not getting hit with direct mid-afternoon sun. Some varieties do not tolerate extremes very well in their first year of getting established to the new growing site. Also check for a bug infestation. It looks like there are 2 aphids on the leaf stalk of the leaf that is standing vertical in the second photo (slightly right of center in the photo).
This was my thought too. If the roots are dead/dying from winter waterlogging you will see this type of dieback in the spring.
If the soil is staying too moist, I recommend removing the tree from its current location. Put it in the shade, as it will not tolerate sun in this condition. (shade or bright shade with adequate air movement) Place it in a pot or cedar box with free draining soil mix (that does not compact or retain a high level of moisture; the roots need oxygen). The pot or box should have plenty of room for extra soil around the root ball (in this case I feel it's better to go with a slightly larger pot or box than normal). Inspect the roots before placing it in the pot or box, and prune off any long decaying roots. Consider using pine bark chips (1" to 2" in length) in your soil mix. Also consider using some sharp stone, to promote fibrous root growth, in my area they sell sharp silica sand that is the size of a match stick head. Sometimes it may take a whole season for the tree to catch itself. Once the trees health and vigor is restored and if it must go back to the same location, I recommend mounding up the soil, so that the tree is planted above the original soil line. This will help keep the roots from staying too moist. Or consider just keeping it in a container in that location. Otherwise you may want to consider a new planting site for this tree next season.
