How to Propagate iris 'Supreme Sultan'?
Propagate by division of rhizomes after flowering, from midsummer to late summer; for more advice, see dividing irises

iris 'Supreme Sultan' · Iris 'Supreme Sultan'
Plant in full sun in well-drained soil, and with the top surfaces of the rhizomes exposed so that they get baked in summer sun, which encourages flowering. See bearded iris cultivation
Propagate by division of rhizomes after flowering, from midsummer to late summer; for more advice, see dividing irises