Iron Chlorosis

In eastern Nebraska, it is common to see slow-growing pin oak or silver maple trees with yellow leaves and possibly some branch die back. Many trees, shrubs, and other ornamental plantings in Nebraska suffer from this disease, called iron chlorosis. It is caused by poorly drained or compacted soils, or by soils with a high calcium content, characterized by pH levels above 7.5. This high pH level causes iron, which is usually present in plentiful quantities, to be tied up in the soil and unavailable for the plants to pick up and use.