Photo: Foliar iron deficiency on river birchRiver birch (Betula nigra) is a popular landscape tree in the Southern Appalachian region (USDA zones 6-7). The cultivars ‘Heritage’ and ‘Duraheat’ have made a good native species even better with resistance to aphid and leafhopper insects. However, river birch demands a soil pH which is moderately acid. Why? […]