Q. We have had these trees in our backyard for 15 years.  All of a sudden, one has a bare spot. What might this be? I enclosed a picture. Not readers but demonstrates dieback in privet due to infrequent or shallow irrigations A. From your picture the plant looks like Japanese or Texas privet. Privets are notorious for looking pretty bad, leaf drop and twig dieback when they are not kept moist. They usually do nicely in lawns or when surrounded by other plants with a similar water requirement. Typically they do not do well in rock mulch and if the soil becomes too dry. So I usually recommend that the rock mulch environment is enhanced with wood mulch or that other plants are included around the base of the plant that require more frequent watering.