Why do olive leaves turn yellow?
Written by
Benjamin Miller
Reviewed by
Prof. Martin Thorne, Ph.D.Successfully growing olives means quickly solving leaf discoloration. Yellow leaves typically point to a problem - my client's tree came back after we handled three issues. The first was overwatering, but especially in clay soils. Let's look forward and examine causes and remedies.
Water & Nutrient Issues
- Overwatering: Let soil dry 2" (5cm) deep before irrigating
- Nitrogen deficit: Apply 10-10-10 fertilizer at 1 lb (0.45kg) per tree
- Iron deficiency: Chelated sprays correct chlorosis fast
Disease Control
- Peacock Spot: Copper fungicide every 14 days
- Remove infected leaves below tree
- Improve air circulation through pruning
Soil testing helps to minimize mistakes and misdiagnoses.I test for pH and nutrients with a simple $25 kit. One time, a client said their tree was ‘dying,' but the soil was perfect. The tree roots were compacted from foot traffic!I aerated the soil with a garden fork and in 6 weeks, the tree color returned.
Water Management
- Use moisture meter ($15) at 6" (15cm) depth
- Drip irrigation prevents foliage wetness
- Mulch 4" (10cm) from trunk to retain moisture
Seasonal Care
- Spring: Balanced fertilizer application
- Fall: Remove leaf debris hosting fungi
- Winter: Reduce watering by 50%
Chronic yellowing requires structural changes. A Texas orchard changed out heavy clay for 40 percent perlite-amended soil, lowering leaf issues by 70 percent. If maintaining potted trees, I suggest pruning the root and replacing the soil every 3 years as well as replacing any salts.
Healthy foliage sustains fruit production. The century-old trees of my Greek mentor are thriving due to tireless care. Yours can thrive as well, but do not delay in addressing yellowing leaves! Weekly, document any changes. What seems catastrophic, can usually be restored with the appropriate action. Your olives rely on those photosynthesizing leaves!
Read the full article: How to Grow Olives: Step-by-Step Guide for Home Gardeners
