Iron Chlorosis in Weeping Oak: Diagnosis, Soil Treatment, and Fertilizer Support

Confirming Iron Chlorosis

Yellow leaves with green veins on a 3-year-old weeping oak in alkaline or clay soil = iron chlorosis. Wire basket left at planting may restrict roots, exacerbating nutrient uptake issues.

Soil Treatment Protocol

1. Drill holes 1-2" diameter, 12-18" deep, 18-24" apart under drip line.
2. Fill with 1:1 mix of ferrous sulfate (20% Fe) and elemental sulfur (90% S). ~2 lbs total for small tree.
3. Timing: Fall or early spring before bud break.

Supplemental Support

• Broadcast 10-10-10 at 1 lb per inch trunk diameter to stimulate root growth.
• Reapply iron/sulfur with fall fertilizer if no spring improvement.
• Results appear next spring—soil chemistry changes slowly.

Product Sources

Iron sulfate (20% Fe), Iron-Sul (20% Fe), or chelated Fe (EDDHA for high pH). Sulfur as Degra-Sul or Agri-Sul prills.