How to Propagate snake's head iris?
Propagate by division as soon as the leaves have died back in early summer

snake's head iris · Iris tuberosa
Also known as: black widow; onion iris; widow iris
Plant tubers 10cm (4in) deep in autumn, in moderately fertile, sharply drained alkaline soil in full sun. Dry summers encourage flowering
Propagate by division as soon as the leaves have died back in early summer