Leaf Damage Can Come from Salts

Q. Do you have any idea what causes deformed leaves to appear on my shrubs? I thought it was from heat this past summer but I also see it on trees not in this sunny spot.

Readers picture of small, deformed leaves from shrub. Except for the scorched leaf margins, the plant looks healthy.

A. If you look at the edges of the deformed leaves on your shrubs, they have brown margins or edges, very typical to salt burn.

            Fertilizer? If too much fertilizer is used or placed too close to the plant, it can cause this kind of brown leaf margins. They can also cause unusual growth. Most fertilizers are salts and can cause salt burn if too much is applied or applied too close to the trunk or main stems.

Extreme salt damage to vegetable leaf

            Salt damage sometimes occurs after a heavy rain. This is because salts are pushed away from the roots with applied irrigation but rain can push the salts back toward the roots. The return of salts to the roots can cause plant damage. For this reason, it’s a good idea to run drip irrigation right after a heavy rain.

Minor salt damage to pepper leaf margins. Enough to cause eventual leaf cupping.

            Salt damage is much worse for plants when air temperatures are hot rather than cool.

            Not enough water applied? This has nothing to do with how often water is applied, how many days each week, but about how much water is applied during each irrigation. Drought like this can also cause smaller leaves with brown margins.

            Salt burn can look a lot like drought.

            Mulch problem? Mulch placed too close to the trunk can cause disease problems when the trunk is in contact with wet mulch too often? This is true of wood chip mulch and rock mulch.

            Zinc deficiency can cause something similar, but I don’t think this is a zinc shortage.

            What to do? Flush the area under the canopy with a large volume of water to wash salts away from the roots. Secondly, pull wood mulch or rock mulch away from the stems or trunk of the plant. Third, add one or two more drip emitters to the plant so as to increase the volume of water applied without having to change the minutes on your irrigation clock.