Problem with mature cherry tree
We have a very large cherry tree about 35 years old that I planted myself. Its main trunk is now about 2' at the base and has 4-5 secondary trunks each about 8-12" in diameter. I do not know the height, but it is about 8' higher than our 2 story house. Until now it has been healthy and spectacular when in bloom with pink flowers. Toward the end of this past summer the leaves of 2 of the secondary trunks on the left of the tree turned brown and shriveled. I brought some sample leaves to Sun Nursery and the person there said it looked like leaf scorch which he said could have either a fungal or environmental cause and that I should wait until spring to see if it comes back. So far, it has not in the areas affected. There also was a thick viscous dripping on the ground under the affected side. I would hate to cut the tree down, but do not know what would be best. I do not like to use fungicides so would not do that. To cut down the affected side would give the tree a very unbalanced look, and besides if it is a disease it may have spread to the rest. It recieves full morning sun, and is really too close to the house. That is because when bought it was tagged a Dwart Kwanzan. Obviously the tag was wrong. The soil is the usual Maryland clay. Do you have any suggestions?
Ornamental cherry trees are often attacked by the peach tree borer (insect) or leucostoma canker (fungus). Both of these kill and cause oozing sap.
There is very little you can do except to keep the trees as healthy as possible so they can outgrow or compete with the damage caused by the pests. Composts or a slow-release fertilizer may be applied, but fertilizer is not medicine and will not solve the problem. Over-fertilizing can make the problem worse. No fungicide or insecticide can reach the problem inside the tree. Here is a link to some of our website info on this: http://extension.umd.edu/hgic/shade-tree-borers
You will have to prune off the dead trunk. If the tree then looks unbalanced, you may be able to remove more of the tree on the other side to even up the canopy. Do not remove more than 1/4th of the tree at any one time. You may have to spread out pruning over two seasons. Prune in early spring--but not before March. Now is a good time.