Hello,

From the images you have sent and the symptoms you have described on your Japanese Cherry (Prunus serrulata) tree. This is indicative of a condition called gummosis. Gummosis is the oozing of sap from wounds or openings in the tree bark and can be caused by various factors, including environmental stress, physical damage, disease, or pest infestation.

Just an FYI: Insects, Diseases, and Other Plant Problems: The Japanese flowering cherry is susceptible to many insect pests and diseases. Insect pests include aphids, borers, scales, spider mites, leafhoppers, caterpillars, Japanese beetles, and tent caterpillars. Possible diseases include dieback, leaf curl, root rot, fire blight, leaf spot, twig cankers, black knot, galls, and powdery mildew. The trunk of the tree is prone to splitting. The tree bark is thin and is easily damaged. It can be a short-lived tree. More information at this link:

Prunus serrulata (Japanese Cherry, Japanese Flowering Cherry, Oriental Cherry) | North Carolina Extension Gardener Plant Toolbox (ncsu.edu)

Bark splitting on Japanese Cherry trees, also known as Prunus serrulata, can occur due to various environmental factors. According to Cornell University, splits can happen on both the trunk and branches, particularly in thin-barked species like certain fruit trees. Young trees or those that are newly planted are more susceptible to this issue. 

Factors contributing to bark splitting include:

Frost Cracks: Severe cold followed by rapid thawing during late winter and early spring can cause splits known as frost cracks.

Environmental Fluctuations: Conditions such as dry weather followed by wet or ideal growth conditions can lead to excessive growth, resulting in bark splits.

Sunscald: This can cause damage to the bark, especially in winter months, leading to peeling of the outer layer in the summer following the damage.

Management strategies involve:

Avoiding Late Fertilization: To prevent promoting new growth that could be damaged by winter conditions.

Proper Pruning: To improve air circulation and reduce the potential for foliar diseases.

Mulching and Watering: To maintain even soil moisture and protect the trunk from damage.

It’s important to note that while bark splits are not typically fatal, they can allow entry of disease organisms which can cause decay. Proper treatment and care can encourage the natural callusing process, helping the tree to close most splits. More information at these links:

barksplitting.pdf (cornell.edu)

Ornamental Cherry Trees: Identify and Manage Problems | University of Maryland Extension (umd.edu)

Here are some steps you can take to address the problem:

Identify the Cause: Determine if the gummosis is due to environmental conditions (like waterlogged soil), physical damage, or a disease/pest issue. If it’s environmental, improving the conditions may help.

Improve Tree Care: Ensure the tree is planted in well-drained soil, receives adequate water (especially during dry periods), and is not subject to mechanical injury from lawn equipment.

Prune Correctly: Proper pruning can improve air circulation and reduce the potential for foliar diseases. Remove any dead or damaged branches.

Fertilization and Soil pH: Only fertilize based on a soil test recommendation and adjust soil pH if needed to ensure nutrient availability.

Mulching: Apply mulch to conserve moisture and protect the trunk, but keep it away from the base to prevent issues with voles and borers.

Because of the of the potential problems this tree might have, I recommend these two options:

OPTION 1:
For a confirmed and precise identification of the problem, I recommend you send all your images by e-mail to the MSU Plant & Pest Diagnostics Lab. The experts there can also provide you with the best treatment options. Their email is <personal data hidden> - Please include your name – The lab will let you know if they need a sample sent. FYI – The lab may also ask for additional images too.

Their website is at this link:

Plant & Pest Diagnostics (msu.edu)

Their Contact Information is at this link:

Contact Us - Plant & Pest Diagnostics (msu.edu)

This link will explain the details on submitting a sample to MSU Plant & Pest Diagnostics Lab:

Submit Samples - Plant & Pest Diagnostics (msu.edu)

OPTION 2

You can consult with a local arborist for a more detailed onsite assessment and personalized advice. To find an arborist in your Zip Code go to this link:

Find an Arborist (treesaregood.org)

I hope this helps!