Summer Tree Care

Q: I’ve noticed that sometimes trees drop their twigs and leaves in the summer. Is this normal for certain species or is this an indication of a problem?

The terms for what you are seeing are “summer dormancy,” “summer leaf drop,” and “cladoptosis,” the latter meaning “a branch” and “falling.” By whatever name, what you see is a reaction to stress.

This may be due to planting a sun-loving species in the shade or vice versa, or it might be a reaction to soil compaction. Saturated soil can also be a cause. More often, however, it is simply due to heat and drought. In this case, the dropping of branches and early shedding of leaves is temporary and harmless. Winter and adequate water should restore the tree to more normal conditions. You might see this in just about any species, but those that seem to do it most commonly are birch trees, maples trees, willow trees, hackberry tree, and western redcedar and its relatives.

The lesson here is: plant the best tree right tree in the right place and, when possible, provide adequate tree watering during prolonged dry periods.


  1. Jean…when you speak with your County Extension Agent be sure to mention how often you water your blue spruce trees. Often underwatering can contribute to the problem and mites are attracted to stressed spruce trees. A simple control is to hit the mites hard with a weekly blast of water to knock down the mite infestation with a garden hose.

  2. Tony…the key is to make sure the landscaper didn’t dramatically change the grade of the soil over the roots of your large oak tree. Just a few inches of extra soil can affect the ability of fine fibrous roots to absorb available oxygen. Please share this web site from the Morton Arboretum with your landscaper to learn more about trees planted too deeply.

  3. I have a large oak tree in the front yard, it had a ring of
    small shurbs under it, inside a brick wall. I had the bricks removed, and the shurbs also. the yard man put down new dirt, and it up against the truck of the tree, then he put new sod down. will that hurt my tree. please let me know, I am 81 years old trying to keep my tree. Thank you so very much. Tony Baker

  4. I have three Blue Spruce trees and the leaves have turned
    brown. I have watered them but I have been told that
    they are infected with Spidermites. Could this be true
    and what should I do about this problem?

  5. I planted a swamp oak in the spring and it was doing well until two weeks ago when it lost all of its leaves.It is alive and I wonder if I need to do anything to help it. I planted it on my farm in Kansas and it has been very hot but it has received plenty of water. It sounds like it is stressed and I don’t want to lose it.

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