Many of our landscape trees are now showing symptoms called scorch, a burnt, browning or discolored look of the foliage, sometimes accompanied by wilting of the petiole or leaf stem. This may be confined to one part of the tree or appear over the entire tree. Often the browning, discoloration or curling starts at the tips or margins of the leaves.
These symptoms can have a biotic (living) cause such as a bacterial scorch disease, or can result from an abitoic or cultural problem. Cultural situations may result from drought, soil toxicity, air pollutants or flooding and often come on later in the summer to early fall with uniform browning of the entire canopy or exterior leaves such as we’re seeing now.
This year (2013), we can attribute much of this decline to our excess rainfall. The tree or shrub is essentially drowning. What’s happening is that the soil has been so wet for so long that oxygen has been in short supply. This would happen particularly to trees that were deeply planted or planted in compacted soil, perhaps even many years ago.
So what to do now? Clean up those leaves when they do fall; keep your fingers crossed and let’s see what develops next spring. If the plant is in otherwise good health it should recover.
Article written by Glenn Palmer, Extension Master Gardener Volunteer.