Cut Back the Peony Stems
First you should cut back all of the stems on your peony. When cutting back peony stems for the winter, I usually cut them back to the ground. However when dividing a peony it will probably help you see where and how to divide the peony if you keep the stems a little longer (about 2-3 inches). A longer stem left on the peony division will also help its new owner figure out the correct way to plant it!
Dig the Peony Out of the Soil
Next, after your peony has been cut back, carefully dig in a circle around the peony. I usually try to dig a circle that is about 1 foot away from the peony stems to try to preserve as many of the roots as possible. After you have dug a circle around the peony, next try digging a little underneath the peony all the way around it, until you are able to lift it above the soil.
Wash Off Your Peony Roots
After you have removed your peony from the soil, you should take it to a place where you can give it a thorough rinse. As you can see I had a little helper to help me with this part! A garden hose with a stream nozzle that has a little bit of power behind it will help get the soil out of all of the nooks and crannies in your peony root.
Let the Peony Rest for at Least One Day
As you can tell from the picture, my peony root is now dry. That's because it's been sitting in the same spot for a couple days. It took me a little while to get back to it. Your peony root should be given time to sit and rest before you divide it. Otherwise you will accidentally snap of lots of your peony's storage roots. When you first dig a peony from the soil, the roots are very firm and easy to break. After the peony sits for a day, the roots will be softer and a little more limber. You should still be careful with the roots because they can still break, but they will be much easier to work with than if you had tried to divide your peony right after digging it.
Find a Nice Spot to Divide Your Peony
After your peony has had a chance to rest and soften up, find a nice spot to divide the peony. Look for a spot that your garden knife will go into nicely and it seems it would be easy to cut. You don't have to divide off one piece at a time. In fact I just divide mine in half and then half again and so on until I get the size divisions I want.
Separate the Peony into Two Pieces
Next after you have separated your peony into two separate pieces, look at each piece to see how many stems and or eyes are on each division. If the roots are large enough you may be able to divide them again, just as I could with this peony. The rule of thumb is that peonies should have at least 3 to 4 eyes on them to grow nicely. If you want a larger plant that will bloom even sooner, you may want to leave 6 to 8 eyes on your divisions.
Examine the Divisions to See if They Can Be Divided Further
If one of your peony roots is large enough that you can divide it into smaller pieces, find a spot on the peony root that the garden knife will fit nicely and allow you to separate it into two pieces with at least 3 to 4 eyes on each piece. Try to make the smallest cut possible so that you don't snap off any storage roots.
Cut the Divisions into Smaller Pieces (If Needed)
After you've divided your division, separate it into separate pieces. Remember not to make the divisions too small. If you have less than 3 to 4 eyes, it could take extra YEARS to get your peony to a good blooming size. So when it comes to dividing peonies, bigger divisions are much better than more divisions.
Separate the Divided Division
Then examine the other half of your original peony to see if it can be divided further as well. If so, repeat the steps above to divide that half into smaller divisions as well.
Divide the Other Half of Your Peony (If Needed)
Find a Spot Where the Garden Knife Fits Easily
Separate the Divisions
Cut the Divisions into Smaller Pieces (If Needed)
Results of the Peony Divisions - 5 Pieces