Red, This question frequently comes up. ~~ Bearded iris are divided and moved shortly after bloom ~~ ************************************************ I moved one once with a budded stalk on it and naturally the stalk went limp from transplant shock. If this is the time of year when you have the time and inclination, go for it. I can't predict bloom loss but the more soil the better (less root disturbance).

You will also find some as dry bulbs or bundled plants for spring planting. Depending on the hardiness of the species, if fall planting is possible, that generally produces best, but in those areas where hardiness is questionable or planting got missed last fall, early spring planting for most will still produce acceptable, if lesser, results. For ornamentals that are left in the ground, they will then produce results in future years indistinguishable from fall plantings.

Wow. You almost have to, don't you? Ask the butterfly peeps maybe? http://forums.gardenweb.com/forums/butterfly

"It is much too hot to work out there and I may wait until late August/early September. Is that enough time for them to get ready for winter? (Zone 5)" Yes. In fact fall is a far better time to move things than summer. And if it is too hot for you to work outside it is much too hot to transplant plants. They suffer from the heat as much as you do and this in addition to transplant stress can set them back. "Should I dig them up and set them out to dry a bit as with Irises? Maybe I can take a day or two to reset the bed while they are removed." I would not let them sit out- in this heat they would dry out. Even in the fall I like to get them into the ground as quickly as possible. If you must leave them out cover the roots with an old quilt or blanket and wet them down. They need to not dry out- they do not have rhizomes like irises. Far better to prep the new bed and even dig the holes before you dig up the plants.