By Linda Vavrus


          ( Linda Vavrus wrote this article for us in 2004. She loved the challenges and rewards of dividing perennials during her visits to Lincoln area gardens through her residential and commercial garden maintenance business, Gardeners-At-Large.  She was also a Lancaster County Master Gardener. It was a great loss when she passed away. The article was so good we could not improve on the subject so we are recycling this.)

          Regular readers of the Neighborhood Garden will recall other articles on multiplying perennial plant stock. This week, we’ll consider division of Bush Peonies.

          You may be noticing, or soon will notice, your peonies are beginning to look a bit ugly with glossy green foliage taking on a rather sickly, mottled appearance, and some of the leaves are falling over. First, relax; they are not really dying!  Second, resist the urge to cut them down to the nubs for the sake of a pretty garden until after we get our hard freeze.   Important things are happening underground as their surface beauty fades.  Your peonies are simply going dormant. But the leaves  (as long as there is some green present) and the plant are still working to make and then store nutrients into the root system (photosynthesis) for over wintering and strengthening next year’s plant, and growing new “eyes” (dormant growth buds) from which next year’s stems will emerge. Do not prune your leaves until you cannot stand their appearance any longer and then prune down to where they are green.

          Why would I want to divide my peonies? If your Peonies are happy, and you are happy with your mature Peonies, leave them alone. After all, you may be thinking, “But Peonies don’t need dividing….ever!” Or “Mine have been in the same spot and are doing fine!”

          However, you may want to consider division if you want to:

(1) Relieve garden overcrowding that can be signaled in large clumps by the      onset of stem and leaf disease or decreases in the number of spring blooms,

 (2) Rejuvenate older plants. Again, you may have noticed fewer and/or                  smaller blooms,

(3)  Multiply the number of Peonies in your garden, or

(4)  The desire to share specimens with family or gardening friends.

          When should I divide? If you decide to take divisions from your mature plants or thin out your crowded Peony bed, late August through September (at least four weeks ahead of the first killing frost) is the preferred time. This gives a division the chance to recover from transplant stress and begin establishing a new root system before the ground freezes.  Remember, Peonies are slow to establish, and a division may take two or three years after replanting to bloom well again.

          How do I divide peonies? Peonies can be challenging to divide because of the thick, fleshy roots characteristic of mature plants.  When dividing old clumps in Lincoln or South Central Nebraska, you will most likely encounter deep, tough roots encased in heavy, compacted soil.  Be sure to allow ample time and have patience when undertaking this activity.

          Here are some steps to help you through the process:

(1) Prepare the soil in advance for the garden area that will house your new division(s) by digging the soil and working in plenty of organic matter and high phosphorous fertilizer like bone meal. Dig and prepare wide deep holes to lessen the time the roots are out of the ground. 

(2) I like to take root “slices” from the perimeter while leaving the mother plant in the ground unless I need to move or remove the whole plant. If you are taking the whole clump, take as much soil as possible and replant. If you are just taking a slice from a plant, you will want to see what you are doing.  I usually cut back the foliage to one or two leaves close to the ground and carefully remove surface soil to expose the top of the crown.  Look for a cluster of three to five newly forming, pink eyes on a section of root that could be cut away in one piece. Unlike a Daylily division where each plantlet has its own roots that can be teased apart from the roots of other plantlets, several Peony eyes may form on a single thick piece of root.  Remember that a larger Peony division will form a new clump more quickly than a smaller slice of root with one or two eyes, and will more likely survive the winter.

(3) Using a shovel or spade, loosen the clump from the soil around the edge of the slice you’ll be taking, digging about 6-8 inches away from the plant.  You may have to dig deep to get under the roots to include some root material with your division and avoid root injury. Do not expect a Peony root in heavy soil to let go easily, Lots of gentle wiggling or cutting may be needed to free the roots. Position a sharp, flat-edged spade or sturdy knife vertically on the crown between your eye cluster and the mother plant. Use good force to slice quickly downward through the root mass to get a clean cut. Then gently leverage the division out of the ground.

(4) As with Iris , hose off remaining soil so you can examine the bare root and then cut away any dead-looking, damaged, or diseased areas of root from your division.  Don’t forget to replace the soil firmly around the exposed root and crown surfaces of the mother plant.

(5) Replant your clump if you took the whole plant, or plant your division as soon as possible in a sunny but not torridly hot, well drained location for the best chance of a successful replant.

(6) Most important:  The eyes should be no more than two inches below the soil surface when planted.  Peonies are touchy about planting depth. Plant eyes too deep, and they may not flower or the fleshy roots will rot. Plant too shallow and the crowns may dry out and die. 

(7) While holding the root section at the correct depth for the eyes, backfill the soil and lightly firm it around the root to set the plant. Water well, and add a layer of loose mulch (not heavy on the crown, however) to help retain soil moisture around the newly planted division and to prevent it from heaving out of the ground when winter temperatures fluctuate.

(8) Finally, think long term when positioning Peonies in your garden.   Be sure to space your divisions at least three to four feet from other plants, including other divisions. Your newly planted Peonies will benefit for many years to come with ample room to grow, thrive and remain undisturbed.

          Before you know it, all eyes will be admiring the large bouquets of Peony blossoms you collect around Memorial Day from the Peony bushes formed from this fall’s divisions.

Copyright 2010