How to Prune iris 'Red Ember'?
Cut back old flower stems after flowering and remove dying foliage in autumn

iris 'Red Ember' · Iris 'Red Ember'
Grow in any moderately fertile, neutral to alkaline, well drained soil in full sun. Plant bulbs at twice their height in late summer or early autumn and feed with a high potash fertiliser after flowering. See bulb iris cultivation for more information
Cut back old flower stems after flowering and remove dying foliage in autumn