September-October Cultural Tip
To avoid over wintering insects and diseases that can cause rot, and to reduce the occurrence of leaf spots and borers, remove and destroy any garden debris, spent Iris bloom stalks, and brown dry foliage each fall.
Cut back remaining foliage to about 6” above the rhizome (this is not required, and is really up to the individual gardener). Trimming the foliage, however, does have its benefits: the garden appears tidier, and the surface area on which leaf spot (a fungus) can develop is reduced.