Q. I live in Oracle, Arizona, and my 15-year-old Arizona rosewood has some dying branches in it. Not the Arizona Rosewood mentioned in the question but it is used in Las Vegas landscapes. A. Dying branches usually indicate a water transport problem, mechanical damage, diseases, chemicals or borers. Arizona rosewood is a 12- to 20-foot-tall xeric tree native to the Sonoran deserts. It is considered a lower water use alternative to oleanders. Arizona rosewood is so new to the landscape industry (less than 30 years old) that not much is known about it. This may require some detective work on your part. It should start to flower and produce small fruit between 6 to 8 years of age so your tree should have started flowering nearly ten years ago.             It is in the rose family so check for damage from borers and fireblight. Other disease possibilities that may include single branch dieback include verticillium wilt.             Even though this is a xeric plant and can handle less frequent applications of water, make sure water is applied deeply and occasionally during the summer particularly during dry periods. Water applications should be about four times each year, particularly during the hot summer months, and to a depth of about 18 inches. The water should be applied to at least half the area under the trees canopy.             There is some discussion about its potential sensitivity to landscape weed killers. Make sure nothing was used close to this plant.