Leaf scorch has many possible causes. Plants that are under stress (such as from drought or heat) may not provide sufficient water to leaves, causing the edges to turn bronze, then later brown and dry. In severe cases, the scorch may spread to areas between veins or entire twigs may die back. Trees placed near heat-reflecting surfaces such as buildings or pavement often suffer from heat stress. Other possible causes of scorch include damage to roots or stem, soil compaction (which can cause reduced drainage resulting in root damage), or the presence of excessive salts from overuse of chemical fertilizers.

Management Options

Non-Chemical Management

Irrigate affected plants during dry periods. Wet the entire root zone, but do not overwater. Try to water oaks deeply but infrequently.
Do not overfertilize.
Avoid injury to roots and trunk.
Heavy foot traffic, construction, and heavy equipment can cause soil compaction and root damage.
Do not plant trees directly against the sunny sides of buildings.
Do not pave over the root zone of established trees.

Select non-chemical management options as your first choice!

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides

None recommended

Images

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Caption: Leaf scorch on oak Photo by: B.M. Johnson
Caption: Leaf scorch on oak Photo by: B.M. Johnson

WSU Extension

Hortsense