Leaf scorch is a common problem among many landscape plants. Contrary to belief, leaf scorch is not a disease, rather a condition caused by environmental factors such as severed roots, limited soil area, or hot, dry winds during the summer.
Moisture is lost so quickly from leaves that the roots canít absorb and transfer water quickly enough. Usually scorch happens during drought periods but can occur even if the soil is moist. Some broadleaf evergreen may even suffer from leaf scorch in the winter. Rhododendron and azalea are a common example.
Scorched leaves turn brown on the edges and between major veins. If severe, the leaf may drop. Leaves may be affected over the entire tree or only on one side. Though scorch can result solely from the weather, the condition of the root system can make plants much more susceptible to this condition. Shallow soils such as those over hardpan or rock lead to a limited root system. This limits the amount of water absorbed through the roots. Also, root damage due to disease, insects, poor drainage or construction can also cause poor water uptake.
To help alleviate damage from dry soils or limited root systems, water once per week if there is no rainfall. Be sure to water deeply with a hose at slow flow for at least two hours. Larger trees will take more water. Mulching landscape plants with a 2 to 4 inch layer of mulch will help conserve moisture. Be sure not to mound mulch next the trunk or main stem of the plant.
Screens or shades may be used on smaller plants for protection. This will help block drying winds. In the future, be sure to select plant material that is best suited for your specific site. Visit your local garden center or nursery for recommended plants for specific locations. Your local County Extension Office can also advise you on recommended plants for Midwest landscapes.