Cherry Trees Dying
Hello, We have 8 fruit trees in our yard: 3 apples, 2 pears, and 3 cherries. This is their 3rd year in the ground. We pruned them last month, and they were looking good. They get 4 gallons of water per week. All of our trees are surrounded with wire to protect them from deer, and all are staked and tied. However, just recently two of our cherry trees have apparently begun to die. One is a Royalton Sweet Semi-Dwarf and the other is a Stella Sweet Semi-Dwarf. They seem to be dying a limb at a time, from the bottom up. Neither have visible pests, though both have some odd peeling bark in places. Our questions are: what is wrong with them? Can anything be done to save them? If not, how can be prevent this from happening to our other trees? Should we be giving our fruit trees more water per week as they get larger? Thanks for your expertise. This is a terrific service!
Deschutes County Oregon
You have a canker on the trunk that could be causing the decline of your tree. The most common cause of cankers is a disease call bacterial canker. This is a very common disease that is found around the world on cherries, peaches, apricots and even pears. Your tree, however, does not display the typical symptoms except for the canker itself. Normally, there would be an oozing of sap and bacterial cells from the canker. Another possibility is that the canker was caused by a fungus disease called Cytospora canker. This will form a dry canker like we are seeing here, but it is less common, especially on young trees. In reality it probably doesn't matter too much as my recommendations will be cultural and apply to both. On any future cherry tree that you plant, be sure to paint the trunk with white, exterior latex paint (50:50 mix with water). This will prevent the splitting of the bark that occurs on cherry trees in the winter on bright, sunny, very cold days with snow on the ground. In this case the winter sun warms the dark bark so that cells become active, but when the sun sets the cells can't adjust quickly enough, killing the cells and causing the bark to split open. By painting the trunk the sun will be reflected off the the bark, rather than absorbed by it. Other than this, fertilizer and prune so that new shoot growth is about 24-30 inches each year and don't over water.
Another possibility for the mortality is the cold weather that we had in mid-November. Cherries were more sensitive to this than apples or pears. In our area, trees were not yet dormant. Where the temperatures dropped to 0 or below we had a significant amount of tree damage and even mortality. There is no doubt that you have cankers on the tree, but that might have been a secondary issue with the main cause of mortality, the fall freeze.