Iris (Iris spp.) foliage is prone to several diseases as well as infestations of insects called iris borers. If you notice any signs of concern during the growing season, you’ll want to remove the infected leaves right away and dispose of them in the trash. It’s also important to cut back iris foliage once the growing season is over — regardless of whether or not you noticed problems earlier in the year. Be sure to cut all foliage back as close to the rhizome as possible and dispose of the clippings. Doing so can help prevent iris borer infestations and foliar diseases from taking hold in your garden!