Leaf scorch is starting to show up primarily on maples around the state.
This is not a disease but rather a physiological problem associated with
damaged roots, storm damage, limited soil area, or hot, dry winds.
Moisture is lost so quickly from the leaves that roots can’t absorb and
transfer water quickly enough to replace what is lost. Though scorch is
usually associated with droughty periods, it can appear even when the soil
Scorched leaves turn brown or, in some cases, turn black from the edges and
between the major veins. If severe, the leaf may drop. Leaves may be
affected over the entire tree or may be affected only on one side. White
pines are also prone to this condition due to the delicacy of the needles.
Though scorch can be due solely to the weather, the condition of the roots
of plants can make them much more susceptible to this condition.
Shallow soils such as those over hardpan or rock lead to a limited root
system that may not be able to absorb all the water needed. Trees may be
more sensitive to scorch this year because of the heavy rains some areas
received in June. Though soils were recharged, in many cases so much rain
was received that oxygen was driven from the soil resulting in root damage.
That root damage is now making it more difficult for trees to provide all
the water needed for the leaves. Also, root damage due to disease, insects,
poor drainage or construction can cause poor water uptake.
To help alleviate damage due to dry soils or limited root systems, water
once per week for recently transplanted trees of every two weeks for large
trees if there is no rainfall. Mulching small trees or shrubs will help
By: Ward Upham