Irises in Rock Garden?
I would like to create a rock garden of irises. The garden size is approximately 10 ft x 10 ft. I would like to plant iris bulbs, leaving a large enough hole for growth, and then sheet mulch (using cardboard) the unplanted areas and then cover the sheet mulch with rocks. Since irises usually spread, my guess is that the sheet mulch and weight of the rocks would prevent spreading. Would this harm any of my original irises? I haven't started the project yet. Thank you. Jane