Thanks to both Oron and Alisdair. There have never been water restrictions in Rome, though they were threatened last summer for the first time in decades, We are hovering around zero in the early morning now so we can offer our Iris friend some cool weather. Bearing in mind that summer days are rarely below 35°C and sometimes around 40°C, do you think I should give some afternoon shade or let it bake?
Thanks again for the identification.