I planted 5-6 ft arborvitae last fall along a parking lot. After a long winter, lots of plowing, and sanding the arbs show alot of brown area on them. I realize that in combination of bad winter and amount of sand/salt this isnt uncommon.Is there anything I can do to better the situation that would help? They are getting plenty of water from a wet spring, and I gave them a dose of holly tone fert. Thanks in advance for your help.