Why Are My Tree’s Leaves Turning Yellow?

It goes without saying that New Jersey autumns are beautiful. It’s all thanks to the gorgeous medley of yellow, orange, and red leaves. You might even spot a few purple ones if you’re lucky.

While we adore these amazing colors, it can be concerning to see them off-season. This is especially true with yellow leaves, which typically indicate a problem. Naturally, if it isn’t fall quite yet, you might wonder why your leaves are turning yellow.


Here are potential causes of those yellow leaves:

1. Lack of Water

Insufficient water is a common cause of yellowing leaves. This is likely if you have automated water sprinklers, which may not reach all of your plants.

A dehydrated tree might have yellow leaves or leaves with brown tips. The leaves might also be dry, wilted, or curling.

To determine if a tree is underwatered, check the soil six to eight inches deep. It should be moist and somewhat cool. But if the soil is dry and crumbly, the tree is thirsty.

2. Too Much Water

Likewise, overwatering can make leaves turn yellow or pale green. Too much water deprives the roots of oxygen, which suffocates and kills them. As a result, the damaged roots are unable to deliver nutrients and oxygen to the leaves.

You can tell a tree is overwatered if the area around is frequently wet. To remedy the problem, take a break from watering your tree. If you have an automated sprinkler, make sure most of the water isn’t falling onto one plant. An environmental factor like a small hill or gutter might also be directing water toward a single tree.

3. Fungal, Bacterial, Viral Disease

A tree with yellow leaves might have an infection. You can identify the pathogen at play by observing other signs and symptoms.

Generally, fungal diseases cause yellow leaves and/or brown spots. There might also be a powdery mildew substance on the leaves. Bacterial diseases, on the other hand, typically cause dark spots with yellow “halos.” Viral diseases cause yellow and crinkly leaves.

If you think your plant is infected, ask an expert tree provider to diagnose the problem.

4. Pest Infestation

Yellow, hole-ridden leaves are likely caused by a pest infestation.

Insects like aphids and mealybugs are notorious for attacking trees. These bugs feed on nutrient-rich sap, making it difficult for a tree to produce enough chlorophyll.

Again, like pathogenic diseases, tree pest infestations are best handled by professionals. It’s the best way to properly control the invasion and prevent it from spreading.

5. Nutrient Deficiency

Trees, like humans, need enough minerals to stay healthy. Specifically, trees need nutrients like:

  • Iron
  • Zinc
  • Magnesium
  • Manganese
  • Boron

If a tree doesn’t get enough of these nutrients, it will have difficulty making chlorophyll, the pigment that makes leaves green. This causes a condition called chlorosis, which turns leaves yellow or yellow-white.

But this isn’t just a superficial issue. A plant needs chlorophyll to turn sunlight into energy and food. Without sufficient chlorophyll, the tree will starve and die.

To identify chlorosis, look at the leaves’ veins. The area between the veins typically turn yellow first, while the actual veins stay green. If the chlorosis is severe, the leaves will be completely yellow with brown spots.

You can reverse the issue by mixing supplements into the soil. An expert tree provider like Friendly Tree can determine which supplements are necessary.

6. Herbicides

Finally, some herbicides lead to yellowing. These weed killers contain chemicals that can disrupt chlorophyll production. Consequently, the leaves turn yellow and the plant is unable to continue photosynthesis.

The yellowing might appear in streaks or spots. In some cases, the veins may also turn pink or purple.


Let Friendly Tree Diagnose All Your Tree Problems

If you’re not sure why your leaves are turning yellow, consult the professionals at Friendly Tree. As you can see, there are many potential causes, so it’s important to work with an expert.

We can examine your tree and diagnose the problem before it progresses. Most importantly, our tree technicians can explain how to prevent the issue from coming back.


Friendly Tree offers tree services in New Jersey. Since 1989, we’ve proudly served customers throughout northern New Jersey, including Montclair, Madison, Union, Morristown, and more.

Contact Friendly Tree at (973) 678-8888 to get a quote or schedule a consultation.