I am new to the coastal south. I have a small crape myrtle (Tonto) which was planted on the northest corner of my house. It gets sun after 12. It appeared to be dark green mold or soot mold covering the leaves last year (new home, new plant). Can this be from the moisture from my irrigation system misting on it, since I have no morning sun on it? I thinned up the trunks this year to about four feet, plus I may be relocating the plant to the front of my yard to get more sun. I have a lawn customer in my development with the same mold problem, but his plant is taller and gets morning sun.