Question: I see a residue on my shrubs and groundcovers after the sprinklers have run. Some of the plants’ leaves are turning brown around the edges. What could the problem be?

Answer: It sounds like soluble mineral salts. Some of our waters have excessive amounts of sodium, for example, and plants may show symptoms of burning because of it. It’s essentially the same thing that happens when we over-fertilize a plant. The soil becomes so saturated with the mineral salts that water is actually drawn out of the root systems, causing the scorching and burning. It might help to incorporate gypsum into your soil. It replaces the sodium with non-threatening calcium, without changing the soil pH. Try to keep irrigation water off your plants’ leaves in the meanwhile.