Black root rot results in the decay of root systems; however, the most obvious symptoms are observed on above-ground portions of the plant. Foliar symptoms include yellowing, wilting, and necrosis (death) of foliage. Above-ground foliar symptoms are the result of root decay; as a result, the reduced root system is unable to take up sufficient water and nutrients to support foliage and stems. There is no cure for black root rot.
Learn more about black root rot from our latest fact sheethttp://www.ca.uky.edu/agcollege/plantpathology/ext_files/PPFShtml/PPFS-OR-W-3.pdf
Other disease-related fact sheets are available at http://www.ca.uky.edu/agcollege/plantpathology/extension/pubs.html#OrnamentalWoody