I planted about ten, 6' tall ligustrums last spring to create a privacy hedge. They developed a bad case of leaf spot fungus. I've tried everything to bring them back to health but they may be too far infected. I,ve been spraying them with fungicide, cleaned all the mulsh and fallen leaves and continue pick up the continuing falling leaves. They keep getting worse. Should I just go ahead and cut them back of all leaves, respray with fungucice and try to let them get started back again?