Answer: Yellowing leaves usually indicate root distress. I wonder if your new sprinkler system is supplying more water than the tree was getting before? If the soil is kept too moist, it will drive out oxygen and the roots will suffocate. I can't recommend anything other than turning off the sprinkler system and going back to your old way of watering. If you notice a change in your tree later in the summer, then the sprinkler system is causing the problems. You may have to move your tree to keep it healthy. Best wishes with your landscape!
Q&A Library Searching Tips