Why Are My Tree’s Leaves Turning Yellow?
Yellowing leaves (chlorosis) are often related to stress, nutrient availability, or watering issues — not always disease.
What’s Actually Happening
Leaf yellowing can result from:
- Nutrient deficiencies (commonly iron or nitrogen)
- Soil pH imbalance
- Overwatering or poor drainage
- Drought stress
- Compacted soil limiting root function
Chlorosis occurs when a tree cannot properly produce chlorophyll, even if nutrients are present in the soil.
Local Context (Niagara)
Niagara soils vary. Some areas have sandy loam, others heavier clay. Soil compaction from construction and landscaping is common.
Trees planted in lawns often compete with turfgrass for nutrients and water.
How to Handle It
- Evaluate watering habits (too much and too little can look similar)
- Assess soil drainage
- Consider soil testing for nutrient levels and pH
- Reduce compaction where possible
From our experience, most yellowing issues we see are stress-related, not disease-driven.
Bottom Line
Yellow leaves usually point to stress or nutrient imbalance — not immediate decline.