I didn't see anyone mention the need to treat for the Iris borer. In Wisconsin, we do this in April, or after it quits being below freezing at night for a period of time. I sprinkle the lawn grub treatment around, but NOT ON the rhizomes. I think the company that makes the stuff I use is Bayers, don't remeber off hand, but it's the same thing you can put on your lawn for grubs. (Maybe they aren't an issue down South?)
