The correct time to divide peonies is about now, August is when they begin to go dormant. Just make sure each division has several eyes, & don't replant deep, the eyes should be no more than an inch deep.

Jaine,
In the past, I've found the website from the American Peony Society to be very helpful.
Maybe your cousin can find some useful information here.

Patti

Here is a link that might be useful: Peony division from Amer. Peony Society

I dug some and transplanted them in winter, just as they were putting out new growth. I think it was February. They resent being disturbed and I only had two tiny blooms from many large clumps.

For us in southwest Missouri zone 6, it begins in September. Just be sure to tell her to barely cover the eyes or she won't every get blooms. They like limey soil and can last 50 years or more so prepare the hole deep and well with lots of organic stuff.

Thanks for that link, Patti. I have to move one this fall.
All my peonies are horribly mildewy & moldy this summer. I have to try mixing up some of that Bordeaux spray.

Yes, peonies hate to be disturbed! If you have to move them, do it in the fall (as they are spring bloomers) and as someone already said, be sure not to replant them too deeply! If they are planted too deeply, they won't bloom. And don't expect a lot of bloom the year after . . . they'll probably pout for about a year until they settle in! As you don't want to move them too often, make sure you pick a location where they have room to spread out a bit, with enough sun, and hopefully a fence or other support to help prop them up. Also, ammend the soil before you plant, as you can't easily ammend after they are in the ground without covering up the eyes too deeply.

I have a question also. I have always moved my peonies in spring, against all advise. Have always had very good luck. But this year I must move 4 huge peonies within the next week or two. When moving them in fall, do you cut back the foliage? When I move them in spring it is just when the eyes are peeking up so not a problem. Just not sure how to do the fall move.

Mary Lu, you are probably getting close to a frost anyway...I would remove the tops just to make it easier to plant the tubers.

Try to put them where you want them so they can remain there permanently. Moving won't kill them, but it will set back the bloom and growth for a couple of years.

Mary Lu, Aug.-Sept. is the perfect time for moving Peonies, the new growth eyes have already formed, this is the time of the year we find them for sale around here. Cut the tops right off this will help get rid of any diseased foliage, botrytis being one of the nasties that affect Peonies. Plant with the eyes just under the soils surface.

Annette

The best time is when the weather goes cold and the plants go dormant. so I would agree that Sept. is the best time to begin the process, although you can still do transplantation well up to spring the following year.

Thanks for the info. My cousin finally decided that since hers are blooming so beautifully, she will wait a couple of years to move them.

Janie