Cherry Tree Problems
Since I last checked in on my little native pin cherry (Prunus pensylvanica), it has grown by several inches and has a kind of skinny, gangly adolescent look. The new growth is encouraging, but I am also alert to signs of trouble. One of the reasons native cherry trees are not often recommended as garden trees in Maine is that they are prone to some problems, most particularly a fungal disease (Apiosporina morbosa) called “black knot” and infestation by eastern tent caterpillars (Malacosoma americanum).
I’m not particularly concerned about the tent caterpillars. I have them in another cherry tree in the woods behind my house, and I used to worry about them spreading to other trees in my woods. I once had a neighbor advise me to remove the silken “tents” from the tree and burn them with a blow torch in my driveway. Since then, I have learned that these insects are mostly cherry tree specialists and are unlikely to spread throughout my woods. I’ve also learned that they are unlikely to kill a tree, and that they provide food for birds. If they show up on this little tree next year, I will probably remove them, but I don’t need to burn them; I can just deposit the silken nest of tiny caterpillars in my driveway and let the birds take care of them.
The two problems I’ve noticed on my little tree involve stems and leaves. There are a few places where stems have been broken and are hanging limply with dead foliage attached. It seems likely that these were physical injuries caused by some animal and not a particular cause for concern. There are also a couple of places where leaves seem to be rough-textured and curling. Nothing I have read suggests that this is an early symptom of black knot, so I will just keep monitoring them and see if the problem gets worse.
I’ve decided to simply monitor my tree this year without taking any action. Next spring, if I’ve decided the tree is garden-worthy, I’ll consider pruning for shape (and to remove any signs of black knot), removing more of its competition, and possibly staking it to gently correct its tendency to lean.
Tree following is hosted by Pat English at Squirrel Basket, where you can learn about other trees being followed this year.