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Cherry Tree Problems

July 13, 2016

cherry tree taller JulySince 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.

cherry tree broken stem cherry tree damaged leaves

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.

11 Comments leave one →
  1. July 13, 2016 5:15 pm

    I think the curly leaves might be psyllium. Which I ignore on my lemon tree. Enough leaves and lemons for me and the wildlife.

    • July 15, 2016 10:09 pm

      Thanks for the identification, Diana. For now, I will ignore it, too. 😉

  2. July 14, 2016 7:08 am

    Looking good.
    “Black knot” sounds very villainous!
    Glad you are mostly keeping pests and diseases at bay – and that broken, dead branch does look just like physical damage.
    Thank you for sharing with us 🙂

    • July 15, 2016 10:10 pm

      Thanks, Pat. I haven’t actually seen black knot, but it apparently is named for its appearance of knotty black swellings on twigs.

  3. July 14, 2016 7:55 am

    Our cherries are riddled with black knot but still grow to enormous heights.

  4. July 14, 2016 11:44 am

    I hope the cherry tree survives its challenges, Jean. I have a problem with tent caterpillars on a perennial lupine and have been giving it close attention as they destroyed a smaller perennial lupine years ago but I’ve never seen them move to another plant – it’s odd that they have such specific preferences.

    • July 15, 2016 10:14 pm

      Kris, Most trees have a high probability of surviving in Maine — which is why this is the most heavily forested state in the US and why I’m always trying to keep volunteer trees from totally taking over my property rather than planting them.
      According to Doug Tallamy, most caterpillar species are specialists that can eat only one or a very few plants. This is why he emphasizes growing the native plants that are needed for the survival of our native butterflies and moths.

  5. July 15, 2016 12:23 am

    I have heard that cherries are prone to problems of all kinds. Despite this I just planted two Prunus virginiana.

    • July 15, 2016 10:14 pm

      Jason, I figure there’s no harm in trying — especially since I didn’t even pay money for this tree; it just planted itself.


  1. Tree following link box for July 2016 | The Squirrelbasket

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