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Caring For Sick Trees In Your Garden

When a tree develops an illness, it's important to take steps to repair or remove it. An undiagnosed sick tree could spread the disease to surrounding trees, or fall, causing damage to property or people. 

Moreover, it may cause fatalities, and in the US, about 100 people get killed by falling trees or branches every year. Here's our guide on how to deal with sick trees. 


Depending on the tree's illness, tree removal services may be needed. However, before moving onto this step, it's important to keep an eye on trees that may display illnesses or damage, and to contact an arborist for the best solution moving forward. 

Signs of a Sick Tree

Signs of a Sick Tree

By keeping an eye on your trees, you can catch some of the early signs of tree diseases. By addressing problems early, you may be able to prevent small problems from becoming disasters.

Amongst the common symptoms of a problem are structural problems. For example, cracks are signs of a sick tree. Cracks may appear naturally on a healthy tree, but deep and widening ones may be a sign of a bigger issue. Trees should also be inspected for overall structural concerns.

Trees should grow upright, and leaning to one side or the other may indicate that the tree is at risk of falling down. Storms or pruning incorrectly can lead to this problem. While this is not a disease, it could lead to the death of a tree.

Decay and deadwood may also be noticed. Decay often appears with an expanded base, dead branches, and wood that is soft and breakable. Deadwood is usually apparent in the branches, which display as dry and easily breakable. This is the most serious concern for a tree that is dead or dying. 

Also read: What to do with Problem Trees?

Canker Diseases

signs of tree disease

One of the most common tree diseases is canker disease. Cankers are areas of dead bark, and, similar to sores on a human, they are caused by bacteria or fungi that can lead to decay.

There are various forms of canker diseases that can affect certain tree species such as poplar, pine, and willow, and it occurs when fungi or bacteria enters the bark through a deep crack or wound.

Once the tree is riddled with canker, it becomes more difficult for nutrients to flow from the roots upwards. If the trunk is the affected part, then it's inevitable that the tree will die. However, if the cankers are in the branches, the tree can be saved by pruning or cutting off the affected branches. 

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Make sure to make smooth and clean cuts while pruning so that your tree can defend itself against deadly bacteria, and clean your pruning tools with a mixture of warm water and a little bleach to avoid contaminating other trees or plants. 

To prevent cankers, it's important to inspect your tree frequently for injuries. Vehicles, inclement weather, pets, and even people can cause damage to trees, so if there appears to be a wound in the trunk, you may need to cut it out to repair it.

Cut out an oval shape around the wound, and let it heal naturally. Don't use sealants as they may interfere with proper healing. Meanwhile, if your tree has deep holes or cavities in the trunk, you can remedy this problem by filling holes with tree filling, but it may be best to leave this procedure to tree experts. 

Powdery Mildew

Powdery Mildew starts out as a grey or white coating on foliage, then later on, the leaves become misshapen, turn yellow, and fall out prematurely

If the leaves of your tree suddenly develop a powdery white coating, it may have a fungal disease called powdery mildew. It starts out as a grey or white coating on foliage, then later on, the leaves become misshapen, turn yellow, and fall out prematurely.

This type of tree disease usually affects plants and trees in areas where there is a lot of humidity. If your area experiences humid summers and has very little rain, you may notice a lot of trees being infected by this fungal disease.

The trees that are susceptible to powdery mildew include oak, apple trees, and crape myrtle. Plants such as lilacs, strawberries, and roses are also more likely to get infected than other types of plant species. 

Preventing powdery mildew from damaging your trees can be a challenge, especially if you live in a humid state such as Florida, Louisiana, Mississippi, or Michigan.

If you're about to start a garden, avoid planting susceptible trees and plants, or plant them somewhere in your backyard where they can get early morning sun. Regular exposure to sunlight will reduce your tree's chances of getting infected. 

You can also spray a mixture of baking soda and water on the leaves at the first signs of fungal infection to prevent your tree's condition from getting worse. 

Check out our guide on How to Use Potassium Bicarbonate for Powdery Mildew.

Using an Arborist

Arborists can even take a look at all the trees on a property and identify any at-risk trees.

When any of these signs and symptoms are noted, it's best to contact an arborist for an assessment. An arborist is knowledgeable in tree health, caring for sick trees, and can provide a thorough assessment of the tree, in addition to recommending the best course of sick tree treatment.

Arborists can even take a look at all the trees on a property and identify any at-risk trees. Tree removal costs can vary depending on the size of the tree and its location, but it's certainly worth contacting a professional rather than attempting the job yourself.

An arborist will review any trees with concerns and assess if diseases are present. For structural concerns, they can brace the trees for support, provide pruning tips, and spray trees with chemicals to prevent any diseases from spreading.

For a tree that is beyond repair, an arborist can also remove the tree, using specialized equipment and recommend trees to replace it. 

Now You Know How to Deal with Sick Trees

These are a few ways that homeowners can keep their property's trees safe and healthy, as well as address any concerns. Keep an eye on your trees in order to maintain a healthy property for years to come. Follow this guide to avoid getting sick trees in your garden. 

About the Author Ann Katelyn

I'm Ann Katelyn, Creator and Chief Author of Sumo Gardener. Since I was a child I've always been fascinated with plants and gardens, and as an adult this has developed into my most loved hobby. I have dedicated most of my life to gardening and started Sumo Gardener as a way to express my knowledge about gardening with the hope of helping other people's gardens thrive.

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