Diagnosing Yellow Leaves on Live Oak: Iron Chlorosis Treatment

Symptoms

Yellow leaves with green veins (interveinal chlorosis) on a young live oak in Florida suggest iron chlorosis—iron is present in soil but unavailable due to high pH (alkaline conditions).

Why It Happens

At soil pH above 7.0, iron becomes insoluble. Florida soils can be alkaline, especially near coastal areas or where limestone is present.

Treatment Options

1. Soil acidification (long-term): Difficult at depth. Elemental sulfur or acidifying fertilizers may help over years.
2. Chelated iron soil application (best): Apply iron chelate (EDDHA formulation works in high pH) under the canopy in early spring. Effective for 2–3 years.
3. Foliar spray (quick but temporary): Iron sulfate or chelate spray greens leaves in days but doesn't fix the root cause.

Recommended Plan

• Test soil pH via local extension office.
• Apply iron chelate (e.g., Sprint 138) per label in March.
• Follow with 10-10-10 fertilizer at 1 lb per inch trunk diameter, scattered under canopy and watered in.
• Mulch 3 inches deep with organic material (not against trunk).

Monitoring

New growth should emerge green. Retest pH annually. Avoid overwatering, which worsens nutrient uptake.