I have a 4 year old Mimosa tree - it survived flooding from Hurricane Katrina in 2005 (brackish water) also sustained flooding from Hurricanes Gustav & Ike (also brackish water) it now has some sort of fungus (gray in color in a bristle-like flowery form) growing on its upper branches - some branches have died but there appears to be some life in it. Can you offer any suggestions? Sure hate to lose such a wonderful tree!