How to Prune Japanese water iris 'Alpine Majesty'?
Remove any dying foliage in autumn, old flower stems can be cut down after flowering

Japanese water iris 'Alpine Majesty' · Iris ensata 'Alpine Majesty'
Grow in moist to wet, deep, humus-rich, neutral to acid soil in sun or part shade; it thrives at the margins of ponds or streams
Remove any dying foliage in autumn, old flower stems can be cut down after flowering