Iron deficiency is a nutritional deficit that can occur in woody and herbaceous plants in landscapes, nurseries, greenhouses, and production fields. It is most often associated with soils that have neutral or alkaline pH (pH 7.0 or above). Plants that grow best in acidic soils are particularly vulnerable to this condition. In Kentucky, iron deficiency is most commonly observed on pin oak, willow oak, azalea, rhododendron, and blueberry, but other woody plants are also susceptible.