Yellow leaves make for fantastic fall foliage. However, if your tree is turning yellow at other times of the year, it’s a sign something could be wrong. Let’s explore some causes and solutions for this common tree problem.

What Causes Yellow Leaves?

Pale green or yellow leaves is known as chlorosis. This happens when trees can’t produce enough chlorophyll — the green pigment that powers photosynthesis. Without chlorophyll, trees struggle to make food, and you’re left with a sick tree showing yellow leaves. Here are the main culprits:

1. Nutrient Deficiency
This is the most common reason for unseasonable yellow leaves. Soils in urban and suburban areas tend to be compacted and/or alkaline, which prevents trees from accessing the nutrients they need to thrive.

2. Water Stress
Roots sitting in extremely wet or extremely dry soil tend to suffer and struggle to absorb water, resulting in yellowing leaves.
Tip: A mature tree typically needs about 10 gallons of water per inch of trunk diameter during dry spells.

3. Pests and Diseases
When pests or diseases invade a tree’s vascular system, the tree often responds with wilting and/or yellowing leaves.

Did you know?

Tree roots extend two to three times the width of the canopy —so the need for healthy soil extends far beyond the trunk.

Ignoring early signs of tree illness can increase removal costs by more than 10 times compared to preventive care. A simple soil treatment might cost $150, while emergency removal of a large tree can exceed $4,000.

Trees weakened by pests or diseases are several times more likely to drop limbs during storms, which can result in property damage and/or injury.

Healthy trees can boost property value by up to 15%, but dead or diseased trees can significantly reduce curb appeal and property value. One neglected tree can turn into a $10,000 loss in resale value.

Seasonal Care Checklist

Spring:
1. Inspect for pests and fungal spots
2. Prune dead or damaged branches
3. Apply mulch (2–3 inches, away from trunk)

Summer:
1. Deep watering during dry spells
2. Monitor for leaf discoloration
3. Treat pests early

Fall:
1. Fertilize based on soil test results
2. Remove fallen leaves to prevent disease
3. Prepare for winter salt exposure

Winter:
1. Protect roots from salt and frost heaving
2. Plan soil aeration for spring
3. Wrap young trees to prevent cracking

Here’s the The Main Idea

Yellow leaves are a warning sign, not a death sentence. With timely action — such as adjusting watering, improving soil, and addressing pests — you can restore your tree’s health and prevent long-term damage.

Concerned about your tree’s health? Schedule a TreeDox TreeScore™ Report today for expert analysis and actionable care recommendations.