In message , Stewart Robert Hinsley
writes

You can find plenty of information on Iris chrysographes on the web if
you want to compare it with the plants you saw. (It's not immediately
clear whether it's bulbous, tuberous, rhizomatous, or what - the T&M
catalog described it as a bulb, whereas WikiPedia lists it among a
group of non-bulbous Irises.)


It's rhizomatous, used to belong to the Sibirica group, habitat would be
wet spring and autumn, damp summer, dormant winter. Transplant now
(there should be green shoots visible) or early autumn.
Unlike I louisiana it's not a water iris: the seeds don't float.

--
Sue ]