Question: Should Iris Plants Be Mulched? Amy J, Miss.
Answer: Bearded irises like the heat and “baked soil” of midsummer. They need no mulch in winter unless there is a danger that freezing and thawing will heave newly set plants from the soil.
In Mississippi, mulching should be unnecessary in winter and even harmful in summer. During the early part of the summer, beardless irises such as the Japanese kinds flourish best in constantly moist soil.
For this kind of iris, a summer mulch might help to retain moisture and, to that extent, would be a benefit. In general, irises need no mulch in Mississippi.
Related: Tips On How To Grow Fine Iris