|Some of our oak trees have leaves that are rusty
looking on the edges and then the leaves die and
fall off. What could be the cause?
|Sounds like leaf scorch, which also affects maple leaves. Drought or heat stress may cause leaf scorch, which happens when insufficient water reaches the leaf margin to keep up with transpiration, or too much salt (from overfertilization) has been translocated to the leaf margins. Here's how to control: When irrigating, wet the entire root zone, but avoid overwatering. Provide good drainage and avoid soil compaction. To avoid reflected heat, do not plant close to buildings or paved surfaces, and avoid rock and black plastic mulches. Finally, do not overfertilize.
Hope following the above guidelines will restore the health of your oak tree.