Time and place in "The Wild Iris" are kind of tricky. We know that the speaker is talking to us, in the present, about something that happened in the past. That much is clear, based on the speaker's use of present tense and past tense verbs ("I remember […] then it was over"). But how long these events lasted or how long ago they happened is left for us to guess.
It's certainly a challenge to figure out where the events occurred. There's a door at the beginning of the poem but no description of a structure to which the door is attached. So instead of picturing a room of some sort, we might be better off imagining a more abstract kind of door. To get in the mood, sneak a peek at "L'embeillie," a painting by the Belgian Surrealist artist Rene Magritte.
By the third stanza, we're on more solid ground ("dry surface") in a recognizable outdoor setting with at least one pine tree and some weak sunlight. The stanza that follows plunges us into darkness, as the speaker recalls being buried alive. Though the idea is fantastical, the setting in stanza 5 remains natural, with references to the "earth" as well as "birds" and "low shrubs."
In stanza 6, the speaker refers to "the other world" and "oblivion" but provides no descriptive details about that world. How would you describe nothingness? While we're still scratching our heads over that one, a "great fountain" suddenly appears. The reference to "seawater" may make us think of the beach, but this time the setting is clearly abstract rather than naturalistic, as the fountain is located in "the center of my life."