dividing your peony roots
Moving and Dividing a Peony - Peonies can be dug up and replanted in your home garden at any time, spring, summer, or fall here in the north.
Reputable growers will sell peonies bare root and as such can only be dug, packaged and transported while dormant. Potted specimines can be planted in the spring providing they have many strong growing shoots. Weak thin stems can be a sign of a small root system, a plant that has been confined to the pot too long, or a diseased root. If you purchase these make sure the price reflects the plant condition as these roots will take longer to establish in your flower bed.
If you are planning to move a peony the best time of course is in autumn when the plant is nearing or in dormancy. The plants start to go dormant when the foliage is rapidly losing color and this usually happens late August or early September after a few hard frosts. The cool soil temperatures allow your peony to start growing a new root system quickly before the ground freezes.
Well grown peony roots are huge and thick; sometimes it is impossible to dig it up with one person, so you can choose to take a wedge out of the peony if you do not want to dig the whole plant. To remove the whole root system, dig about ten inches in a circle around the plant going about eight inches deep. Then undercut the plant lifting the entire root ball out of the hole.
It is better at this time to divide the peony rather than resetting it in the hole as an entire plant. The disturbance of the root system by pulling it up is such that it takes the plant years to re-establish the root-to-top balance ratio that is needed for health flowering. Smaller root divisions recuperate from the shock quickly and establish much faster than a whole specimen. Alternately, you can “heel” the whole plant into the garden if you dig it up early in the summer and then dig it up again to divide it when the cool season arrives and better growing conditions exist .
If you are dividing it in the autumn, once the root ball is out, wash it carefully and then let it rest in a shaded spot for a couple of hours. This allows the roots to become flexible and will be easier to divide. The root can be an imposing mass at first, but carefully cut off all parts that seem dead. Then look for the new pink or white buds and cut down the center of the crown allowing each bud section to have a corresponding root system. Peony divisions of 3-5 eyes seem to recuperate well, any smaller and it can take five years or more to bloom. Let the new pieces dry for a day or so in damp peat moss or paper before replanting.
If you are dividing the peony with green foliage still attached do not let the root sit and dry out, replant the divisions immediately.