Pin Oak Iron Chlorosis: Soil pH and Treatment

Wichita KS mature pin oak: 1/3 SE canopy not leafing, leaves thin/yellow. Dead lower limbs. Nearby pin oak also yellow. Pruning now okay?

Diagnosis: Iron Chlorosis

Yellow leaves, green veins = iron unavailable due to high pH (>7), clay soil, or root damage from fill/compaction. Pin oaks highly susceptible.

Treatment

• Soil test via extension (tell them it's pin oak with yellowing).
• Apply ferrous sulfate + elemental sulfur in holes 12–18" deep, 18–24" apart under drip line. 6 holes, 2 lbs total for small tree.
• Or use iron chelates (EDDHA best for high pH).
• Fertilize 1 lb 10-10-10 per inch trunk diameter.

Sources listed for iron/sulfur products.