Cause Drought, heat stress, and excess sunlight may cause leaf scorch. In general, there is not enough water reaching the leaf margin to keep up with transpiration. An interruption of the vascular system, as with cankers, can also produce these symptoms. Salt damage may occur on plants growing near sidewalks due to winter use of de-icing products or from over-fertilization. Some lindens including Tilia americana (American linden or American basswood) are reported to be intolerant of air pollution and may develop marginal leaf necrosis or other leaf damage if exposed to high levels of pollution.
Symptoms Leaf margins and areas between veins turn brown. Twig dieback may follow. Sun or heat related stress will occur primarily on the south side of plants.
Cultural control
- When irrigating, wet the entire root zone infrequently during the summer. Avoid over-watering.
- Provide good drainage and avoid soil compaction.
- Use a layer of organic mulch over the root zone to retain soil moisture and to moderate soil temperatures.
- To avoid reflected heat, do not plant close to buildings or paved surfaces, and avoid rock and black plastic mulches.
- Avoid root and trunk injury.
- Do not over-fertilize.
References Hammerschlag, R., Sherald, J., and Kostka, S. 1986. Shade tree leaf scorch. J. Arboric 12:38-43.
Cekstere, G., Osvalde, A., and Vollenweider, P. 2016. De-icing salt impact on leaves of street trees (Tilia x vulgaris) in Riga, Latvia. Acta Biol. Universit. Daugavpil 16:31-38.