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Helping A Tree Recover From Gummosis

Trees are an important aspect of the yard, so losing one could be very detrimental.

Last spring we had a Yashino tree become infected with Gummosis. If any of your trees have experienced this then you know it is an oozing of sap from the wounds of the infected tree. The sap is usually coming out of a canker that hasformed on the tree.

There can be many reasons why your tree has Gummosis such as a wound, environmental stress, and/or disease.  What I didn’t know is that over-watering can cause gummosis, which is an environmental stress. Also, a late frost can cause stress on a plant especially if it has started leafing out or blooming. The late frost makes the tree think of dormancy again but then a day or two later there are 75-degree days.

The best way to help the tree recover it is to remove any oozing you see and spray that area with horticulture spray. The spray will kill any fungus in the oozing sap and help protect the tree from reinfection. It is good to point out that there could be many spots on your tree that are oozing from the cankers so make sure you remove each one and spray. If there are any infected branches remove those and burn them immediately. This will kill the fungus and keep it from spreading to the rest of your trees.

As a good cautionary practice spray the surrounding trees that are close by with the horticulture spray for a layer of protection. Keep an eye on those surrounding trees as well over the next couple of months to make sure they are not showing any signs of infection.



When first noticing the Gummosis on the Yashino tree I immediately started pulling off the sap. Some of the damage was done for the season in 2023 but in 2024 I had to remove the cankers and do a fertilizer treatment.



The next part of treatment is wound healing spray. After I removed the canker I sprayed a horticulture spray that kills fungus and allows the tree to begin healing. I only sprayed once, if you feel as though you need a second round then wait a couple of days before a second dose. After the spray dries you can come back with a wound healing spray to close up the wound and protect it from bugs and ants.




Removing The Cankers

Before the tree could start to heal I would have to remove the cankers. To do this I used a small pruning saw. I gently laid the pruning saw flat on the tree above the canker a just started sawing. My objective was to find new wood below the canker. Some of the cankers were about an 1/4 of an inch thick. So a a trunk that is only an inch and half thick you can imagine this is deep. Removing all cankers is very important to the future health of the tree. You can catch all the sawing debris in a cloth or newspaper placed around the bottoms of the trunk. Dispose of this by burning it as it has the fungus in the canker sore.



Fertilizer Treatment

Although you may think that there is a special remedy that will cure gummosis. From my own experience I have found that an organic fertilizer that won’t burn the roots if you use too much or have to breakdown like granual synthetic fertilizers.

To help the Cherry tree get the nutrients it needed to repair and relieve the stress I used Dr. Jim Z Tree Secret. It is very easy to use and I saw a difference in about 2 weeks after the first application. Since the tree I am treating struggled for about 6 months I am giving it 1 dose for 4 months. I started this in April so at this point in writing this article I will do one more in June.


At this point there is no known foreign viral or bacterial cause but after environmental stress is present the tree is very vulnerable to outside pests and diseases. It is always good practice to keep a sharp eye on your plants especially young trees. If you notice gummosis on any of your trees start with the steps of treatment I have discussed in this article for best results.

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