Leaf scorch may begin as yellowing, then browning, then expansion of the damaged area. In some plants it will continue to move between the veins of the leaves. Winter leaf scorch in plants such as rhododendron usually appears as two long, brown areas paralleling the main leaf vein. Narrowleaf evergreens show leaf scorch as browning of needle tips. As unfavorable conditions become more severe, browning of needles increases.
Symptoms usually appear after drying winds in conjunction with periods of hot, dry weather.
Scorch may also suddenly appear when long periods of wet, cloudy weather are followed abruptly by windy and sunny weather. Symptoms may appear on only one branch or one side of the tree, or may be spread over the entire tree. Usually the side of the tree exposed to damage, wind, sun or other unfavorable conditions will show injury first. Causes Scorch usually is a warning that some condition has occurred or is occurring that is adversely influencing the plant. In some cases it is simply an indication that a particular tree is unsuited to the local climate or has been given unsuitable exposure.