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Question from Kort, UT (received 8/28/20) -
Last fall I planted about a dozen chokecherries in my yard and a few of them are dying. Is that something you could help me with?
The stems get this dark, sappy mark and then eventually die. There's very small bugs crawling around in the soil near the wound Help!
Thank you,
Kort
Answer from Dr. Mike Kuhns, USU Extension Forester and Professor (sent 9/1/20) -
Kort,
At least one of the trees (the first shown) has a stem canker right at the ground line and it looks like it has girdled and killed more than half of the circumference of the largest stem. Many members of the cherry genus in the rose family are very susceptible to diseases, including fungal cankers. They usually will cause some brown, clear exudation where the canker is in the tree. This exudation is called gummosis, but it is more of a symptom than a disease itself. Gummosis can be caused by a canker, but it can also be caused by physical damage to the stem or many other things.
It is not clear to me whether the trees were planted too deeply, or if I am just seeing a multi stemmed tree. However, usually the branching for a multi stemmed tree occurs above ground. So check on whether they are planted too deeply now, or whether they were actually grown too deeply, which unfortunately is fairly common.
I suspect that your trees came from the nursery with cankers, but it would be hard to tell at this point. All you can do now is make sure that the trees are getting enough water so they have a chance of outgrowing the canker. If the root collars were planted or grown too deeply then it may be possible to remove the surface soil and expose the root collars. Good luck!