I do not recall ever meeting a gardener who disliked peonies. What could one possibly hold against a peony? Spectacularly beautiful, supremely fragrant, and require so little in care. The only improvement would be if they could somehow bloom longer throughout the summer. Their season lasts but a few short weeks. Luckily their glossy cut leaves are attractive in the landscape while not in bloom. I started gardening around age six, and still remember being in awe of my next door neighbor’s peonies that exploded into bloom seemingly overnight. Decades and dozens of peonies later, I am still bewitched by them every year. Peonies are extraordinarily long-lived and quite easy to transplant, so it is common for gardeners to dig them up and bring them from house to house through the years. This past fall, I was gifted several peonies from a friend that were originally planted in the early 1950s in Ohio, moved to Virginia in the 1990s, back to Ohio in the 2000s, and finally to my garden in 2013. A plant of substantial versatility and vigor. Because peonies grow on rhizomes, with time and judicious division, one plant can turn into dozens.
Although peonies do not need to be divided all that often. Most peonies will go lifetimes without ever being divided. Often gardeners choose division to multiply the plant. A peony will tell you it needs to be divided when its bloom becomes increasingly less prolific or stops all together. According to OSU FactSheet HYG-1241-94 “Carefully lift the clump and wash away the soil to expose the eyes. Using a clean, sharp tool, divide the clump into sections, each with three to five eyes and good roots. Replant immediately.” Eyes are the red colored buds on the rhizome. Although peony division can be done in the spring as soon as the soil is workable, late September or early October is ideal. Although a peony refusing to bloom may not necessarily be fixed by a division.
There are a few other problems that can cause a peony to stop blooming. The most likely is that the rhizome is planted too deep. This can happen easily because even after just a few years of annual mulching, the peony that was adequately close to the surface could now be far too deep. Peonies prefer to be planted surprisingly close to the surface. About two or three inches below. Whereas many other plants would not survive a winter with so little cover, peonies require a deep chill in their dormancy. Established peonies are surprisingly hardy. All the way down to zone 2. Although if you do plant new peonies or divisions in the autumn, it is a good idea to mulch them through the winter and brush it away in the spring. Another common thief of blooms is inadequate or excess nutrients. The best way to assess what the soil has too much or little of is to have it tested at the OSU Extension Office. If the soil around a peony has too much nitrogen, the plant will likely produce a mass of healthy looking foliage but few to no blooms. To identify a deficiency of potassium or phosphorus is harder because there are no telltale signs other than lack of blooms. When looking for a fertilizer it is helpful to have an assessment of your soil’s nutrient content. For my peonies, I use a 20-40-10 (or 2-4-1) organic seaweed emulsion that has always worked very well. The three numbers in fertilizer go N-P-K, so my 2-4-1 fertilizer has 2 parts Nitrogen, 4 parts Phosphorus, and 1 part Potassium. Most commonly fertilizers are equal 20-20-20. If there is a surplus or deficiency, adding an equal fertilizer will maintain the imbalance but at higher numbers.
Also included in OSU FactSheet HYG-1241-94 is a list of different peonies for different bloom periods. With a variety of peonies planted, the season of bloom can be extended up to six weeks. This is a partial representation of the list. The complete list and a link to this FactSheet can be found on the Delaware County Master Gardener Blog at www.mgdelco/blogspot.com
E - early bloomer
M - midseason bloomer
L - late bloomer
P. ‘Bowl of Beauty’ - rose pink - E
P. ‘Krinkled White’ - white - M
P. ‘President Lincoln’ - deep red - LM
P. ‘Seashell’ - pink - M
P. ‘Kansas’ - brillant red - E
P. ‘Festiva Maxima’ - white - E
P. ‘Nick Shaylor’ - blush pink - L
P. ‘Fairy’s Petticoat’ - dainty pink - E
P. ‘Sarah Bernhardt’ - med. rose pink - Mzsdcffv
Stephen Jones is a Delaware County OSU Extension Master Gardener Volunteer