How to Prune dwarf crested iris?
Remove any dying foliage in autumn, old flower stems can be cut down after flowering

dwarf crested iris · Iris cristata
Also known as: lady's calamus
Grow in moist, humus-rich soil in full sun or partial shade. Or grow in a container under glass, keep just moist during dormancy
Remove any dying foliage in autumn, old flower stems can be cut down after flowering