|Japanese blueberry with dead top|
I also attached a better photo of the trees directly adjacent to them (6 total trees, 4 are thriving/2 appear to be dying). These were all planted at the same time and it’s interesting that the two on the end (which are having problems) never grew as tall as the other 3.
|Dead top of the Japanese blueberry|
A. Yes, it appears to be sunburn. Just cut it off but this is exactly what can happen to a tree in a death spiral. It gets sunburn perhaps because the tree trunk was not shaded by enough canopy.
The sunburn causes the top to dieback which opens I more to sunburn. Borers come in and causes the tree to dieback more, sometimes killing it. You have no choice but to remove the dead part. Sometimes painting the exposed area of the tree with diluted white latex paint can help. It helps to lower the surface temperature of the limbs and reduces sunburn.
Sometimes just attaching some burlap loosely over the area and tying it in to it does not blow off can help until there is new growth that covers the area.
|Burlap added for some temporary shade|
Plants like Japanese blueberry, Podocarpus and others (often in the rose family or Prunus genus) gets sunburn due to very thin and tender bark.
Hope that helps.