Crabapple and apple tree issues

This crabapple usually has bigger, red leaves (per owner) and this year, leaves are smaller and canopy is sparse with some die back. Overall, the leaves just look smaller, didn’t see any evidence of insects. Bark is also peeling. Owner says any lawn treatments done in the area are granules, not sprays.


Apple tree (owner said it is some type of apple, produces flowers but never apples), also is looking more sparse this year. Close up of the branch and leaves is from this tree. Owner applied fertilizer spikes around this tree about a week or two ago, but it was looking like this before that.

I was guessing winter and environmental stress from the weather this year, but any other suggestions for the owners?



  1. When a plant is sick from other than nutrient deficiency, I would NOT fertilize. It does NOT improve the health of the tree and can make the problem worse. Fertilizer uptake is an energy requiring process meaning the plant root has to use energy from an already sick plant to uptake the nutrient ion. Getting to the root of the problem, pun intended seems to be what is needed. Yes, I see apple scab on the tree which causes defoliation and a sick looking plant. Years of defoliation from apple scab weakens a tree that it cannot defend against other, more serious pests, like root rot, cankers, vascular wilts, etc. The bark peeling off on crabapples and apples is normal, some cultivars do more of this than others. The lack of fruit production may be due to poor pollination, especially if he sprays during bloom time, he will kill the bees. Bees are needed for many plants, especially fruit crops. Apples and crabapples need cross-pollination for fruit set, meaning a nearby crabapple or apple tree is needed to cross-pollinate with their crabapple tree. There are only a couple fruitless/sterile cultivars of crabapples, hence they would not produce any fruit. I have seen some cultivars of crabapple produce reddish new leaves, similar to maple trees. It is normal, unless there is also interveinal chlorosis (leaf yellowing with veins remaining green), then I would suspect a problem. Crabapples and apples are very cold hardy so I don’t think that would be the issue unless there was a severe cold spell during blooming. Apple scab and frog-eye leaf spot look similar to me and both will cause defoliation. I would make sure the root flare is visible at the soil line and the tree is not going into the ground like a telephone, which puts roots deep into the ground, away from good porosity and aeration. This happens when the tree is planted too deep.

    • Thanks Brian and Laura for the helpful information! What owners want to know is not only what the problem is, but what can they DO?
      A couple of notes – the owners fertilized on their own before they contacted us. According to the owner, the crabapple normally produces red leaves, but this year didn’t and produced smaller, green leaves.
      According to the owner, the apple tree has never produced fruit (he said it was “some sort of hybrid that doesn’t produce fruit”), so lack of fruit production was not a concern and I don’t think they do any spraying.They were more concerned about these trees looking “sickly” and wondering if there is anything they can do to help. The trees are probably about 15-ish years old (owner planted them). Thanks again. I would appreciate knowing any additional suggestions, or if there is honestly no hope for these trees.

  2. Julie:

    Control recommendations for apple scab are in the fact sheet that I referred to in my previous post, including spray treatments if your clients are so inclined to use these. I have seen trees defoliate from this disease for many years and still continue to bloom. I don’t consider it a fatal disease. As Laura pointed out however, stress from continued defoliation can make trees more prone to more severe diseases.

    If there are root rot problems, testing of the roots to determine which pathogen(s) is(are) present would be needed before I could make any sort of treatment recommendations.

    For info on Japanese beetle and its management, see You can also consult with PJ Liesch, the UW-Madison/Extension insect diagnostician, about Japanese bettle as well. His contact information is (608) 262-6510 or

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