sparse leafing on ornamental crabapple

Asked June 20, 2017, 10:41 AM EDT

I have an ornamental Ozark crabapple tree. This year it has scant foliage. Is it winter stress, fireblight, or a fungal disease? I'm not sure what the problem is so I don't know how to deal with it. It has produced a lovely, dense canopy previously. We had a mid-March blizzard this year and received over 42" of snow. Could the late snow have causes the problem?

Otsego County New York

4 Responses

There are a number of issues that could be affecting your crabapple tree and it would be helpful to know if you see any evidence of insects, infection or unusual growth on the trunk, twigs or the leaves (few as there are) on the tree. A close up photo of the existing leaves and any other issues you uncover would be most helpful. Also, would you please have a look at the lower bark and see if you see any gaps.

I apologize for giving you the extra homework but we want to get the clearest picture possible so we can offer the best help.

Many thanks!

Thank you for responding so quickly. I've been so concerned about the canopy, that I hadn't looked at the trunk very carefully. I didn't see any unusual insects around the tree. Here are some photos. I appreciate your help.

Thank you for the additional photos. The split in the trunk is of some considerable concern as it indicates a tree under stress. Bark splitting is not uncommon on thin barked trees like crabapples. Increasingly erratic weather patterns - alternating periods of extreme warmth and freeze in the winter and drought and flood in the growing season - are usually the reason. The bark and the tree's core are warming, chilling, drying and hydrating at different rates. If this split is on the southwest facing section of the tree, it could be sun scald. This is the result of late afternoon sun hitting the bark of the tree, sometimes reflected off the snow, on cold winter days.

A young vigorous tree will repair itself from this sort of damage most times. An older tree may or may not. And while I can't quite tell the depth of this split, it appears to go well into the surface of the tree which is unusual.

You can help your tree by making sure that the cultural conditions in which it is growing are the best possible. Make sure there is nothing shiny nearby reflecting bright sun onto the bark. It would be helpful to make a soil analysis to see if there are any nutritional deficits that could be adding to your tree's stress. If you would like to do that on your own, you can get instructions on preparing a sample and expert analysis through your Schoharie and Ostego County Cooperative Extension. The soil analysis will also tell you if your soil is within the right band of pH to make the nutrients in the soil available to your crabapple.

There may be more going on with your tree. The crack in the trunk may be a access point for insects or disease. Any unusual appearance of the leaves may hold a clue to additional troubles. It may be well worth consulting an arborist to assess the soil, depth of injury to the trunk and any other factors evident on closer inspection and suggest a course of action.

Best of luck with your tree. Please let us know if we can be of further help.

Thank you. I will follow up with a soil analysis. I did one last year and the soil pH was 6.