Can my Magnolia trees be saved? We planted them approx. 3 years ago, and they have done fine since then. This winter the top leaves turned brown. We have 2 others that have no brown leaves on them and are very full. These 2 are not doing so well. We live in San Antonio, Texas and have a sprinkler system that waters 3 x a week for 15 minutes, although this winter it was not on. I also noticed a the white dots on the leaves, but they are on the thriving trees also. I would like to do whatever it takes to save these trees before it is too late. Thanks for any help.