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HERBACEOUS PEONY CARE

It's Peony Planting Time
Whether you are noticing the approach of spring or the onset of fall, it is the perfect time to plant herbaceous peonies.

Bare-Root or Potted Herbaceous Peonies
Healthy herbaceous peonies consist of two or more carrot-like roots with 3-5 eyes at the top of the crown. Bare-root herbaceous peonies are planted September through early April. Potted herbaceous peonies are planted in May and June.

Site Selection
First, consider the amount of sun. The more sun an herbaceous peony has, the better it will grow. Planted in less than full sun, a herbaceous peony will take longer to mature and flower.  Full flower forms like rose and crown hold up well in hot afternoon sun, while lighter flowers forms like single and anemone need protection from hot afternoon sun. See guide to shapes and colors for help in selecting which cultivars best suit your garden.

Herbaceous peony's grow well in zones 3-8. We do not recommend planting peonies outside of these zones as they will not survive. For more information on your horticultural zone visit the National Gardening Associations website.

Second, consider soil conditions. Peonies tolerate a wide range of soil conditions. Ideally, you want a neutral to slightly alkaline soil that has good drainage and high organic content. Peonies planted in clay soil, amended to ensure good drainage, take longer to become established but produce beautiful flowers for generations as clay soil retains nutrition.  Peonies planted in sandy soil take less time to become established but can produce less striking plants as nutrients easily leech out of the soil. If planting in sandy soil, amend with clay and compost and top dress several times a year with compost to renew the soil. Be cautious when top dressing as this can increase the depth of your plants and plants that are too deep will not flower, see the planting section for details.

Regardless of soil conditions, herbaceous peonies need soil that drains, as peonies cannot tolerate wet feet. 

Amending Your Soil
Look to create a friable loam - soft, dark, rich, loose, soil that has relatively equal proportions of clay, silt and sand. These soil conditions will allow for free water flow while retaining the nutrients in the soil.

If you have clay soils you will need to amend for drainage. A good solution is to mix compost and rock dust into your soil. Rock dust can be obtained from a neighborhood quarry. Gypsum, a type of rock dust, can be obtained commercially from garden centers. Rock dust has the benefit of adding micro-nutrients to the soil.

If you have sandy soil amend with clay and compost to increase the retention of nutrients.

Herbaceous peonies tolerate a wide ph but prefer a neutral to slightly alkaline soil, a ph to 6.5 - 7.5. If you are unsure of your soil condition or ph, you may want to get a soil test from your county’s agricultural extension service.

Planting
As your peony prefers to be planted and left in one location for generations, it is worth taking the time to amend the soil as above.

To plant, dig a hole the size of a three-gallon pot. You may want add a slow release fertilizer that is low in nitrogen, such as bone meal or bulb tone.

Plant so that 0.5 to 1.5 inches of soil cover the top of the root and water in well. Press down on the soil to remove air pockets in the soil around the root and lift the root as necessary so it does not settle more than 1.5 inches beneath the ground. The depth should be matched with your horticultural zone. For example, most of Virginia will plant peonies .05, northern New Jersey will plant at 1.0, and Maine will plant 1.5 inches below the surface of the soil. Planted too deeply flowers will not develop, too shallowly and the tops of the eyes will freeze and die back in the winter. Avoid mulching your herbaceous peonies as this will insulate them and they may not flower.

During the first two growing seasons after planting a new peony, ensure that it gets a good soaking every two to three weeks. This will allow the plant to get enough water while the fibrous root system becomes established. Remember that peonies do not like wet feet and be careful to not over water.

What to Expect
Peonies, like most perennials, take three years to become fully established in your garden. They follow the well known truisms - first year sleep, second year creep, third year leap - or first year roots, second year shoots, third year flowers. You will see some flowers before the third year, but it takes three springs before the plant has a mature and stately presence. Herbaceous peonies can live for decades in one place without needing to be moved or thinned.

Fall Care
Around Halloween, cut herbaceous peony stems so they are two inches above the ground, see the pictures below.  It is common at this time for the leaves to be less than aesthetically pleasing.  They may be dotted with brown spots or covered in a white mold.  These diseases are common and largely cosmetic but should be removed from the garden.  Clean up the area around the peony.  Add compost six inches around the base of the stem, not on the peony. If desired, add fish and seaweed emulsion, bone meal or a slow release fall fertilizer according to package directions.  Carefully check the surface around the stem to ensure the pink or white eyes remain 0.5 to 1.5 inches below the surface of the soil depending on your horticultural zone.

Fertilizing Peonies
Peonies typically thrive with neglect and therefore need little fertilization.  First consider the environment.  Is a chemical fertilizer necessary? If so choose a balanced slow-release one like 5-5-5 or 10-10-10. Rarely, do we use chemical fertilizers at Peony’s Envy. Instead, we compost all the time.

We spread 120 to 180 cubic yards of mushroom compost on the gardens every year. Hy-Tech Mushroom is a company in Pennsylvania that has the very best compost.

We use Neptune’s Harvest™ fish and seaweed emulsion by the gallon both as a foliar spray when leaves are emerging and as a root drench both when planting and during fall cleanup. Other options for fertilizer are well-decomposed compost, bone meal (be wary if you have digging dogs or raccoons), bulb tone, or rock dust. When applying compost be careful not to a thick layer as this could increase the planting depth and reduce blooming. The best way to apply compost is by mixing it in a ring around the peony.

Diseases/Insects
To prevent disease make sure your garden is kept clean, that air circulates, and that plants are kept healthy. Messenger™ and Neptune’s Harvest™ are two organic products to keep your plants healthy and disease resistant.

Powdery Mildew - leaves turn white. Onset is in late June through September.  It is not fatal and tree peonies are less prone than herbaceous peonies to this fungus. In some years powdery mildew is worse than others. It can infect plants when there are hot days, high humidity, and cool nights. Once the plant is infected, simply remove the leaves for no amount of spray or oil will rid the plant of powdery mildew this year. Some preventative remedies include the following: Bacillus subtilis to boost plant’s natural defenses, rhubarb leaf tea, backing soda spray (1t backing soda, 1qt. water and a few drops of liquid soap), cornmeal as a soil amendment or mixed as a spray, neem oil, products containing sulfur, or a biofungicide recommended to treat powdery mildew on peonies. The cooperative extension service in New Jersey recommends potassium bicarbonate at 7-10 day intervals.

Botrytis - young stalks wilt and die, buds turn black. Onset is in early spring when temperatures remain below 70 degrees. Botrytis will kill tree and herbaceous peonies if not treated. Botrytis thrives in cool humid conditions and can be minimized by planting peonies where they have good air circulation. When noticed, cut off diseased portions of the plant, dipping the pruners in a 10% solution of bleach between each cutting to ensure the disease does not spread. Throw out the diseased portions; do not compost. A more aggressive option would be to use systemic fungicide labeled for use on peonies. The cooperative extension service of New Jersey recommends ferban, maneb, and triflumizole from the time buds are pea sized until plants are ready to bloom to prevent botrytis.

Various Fungii/Diseases - There are several diseases that can cause blotches on the leaves or cause the plant to turn black, wilt and portions to die. When in doubt, send a sample to your county’s agricultural extension office for laboratory diagnosis and treatment recommendations. But in general peonies are disease resistant and require very little care.

Ants - We have heard for generations that ants are necessary for peonies to flower. This is not true. The ants are simply attracted to the nectar on the buds. Ants keep the garden clean of other pests and will not hurt the flowers or the leaves.

Chafer Beetles - peony flowers being eaten. Chafers are beetles look similar to Japanese beetles. They can be removed by hand or killed with almost any insecticide. Neem oil is an organic option, read the product label for more detailed instructions.

The Best Cut Flowers
If you are worried about ants when bringing cut flowers into the house simply cut the flowers when the buds are still closed but soft. The buds start out as hard marble like formations and as they begin to open they get soft like a marshmallow. Cut the flowers at this stage before the ants have found their way into the heart of the flower.

Cutting the flowers when the buds are soft allows the flower to open at a slower rate as it is opening in the cool of your house instead of the heat of the garden.

To preserve your flowers for weeks after their bloom time simply cut them in the stage stated above and store them in the refrigerator. They can be stored with or without water, placed on their side, wrapped in damp paper towels and cling wrap, for up to four weeks. Remove them a few days before your big event and they will open fully in your house. Note that peonies stored for a long period of time will open faster and not last as long.

Peonies Not Blooming?
If you have old established peonies that have beautiful green leaves and no flowers it is often a problem with planting depth. This can be due to a number of reasons such as years of mulching or shift in the garden. To check the depth of your peony carefully move the soil from the top portion of the plant being careful not to break off the delicate pink eyes. The top of the root should be from 0.5 to 1.5 inches below the surface of the soil. Another possibility that should not be ruled out is amount of sunlight. Over time surrounding trees and shrubs can shade out your peonies resulting in fewer and fewer flowers.

If the overall health of your plant is declining check planting depth, the amount of water, competition of roots, depletion of nutrients in the soil, etc. It may be time to transplant your peony. Divide it when you transplant it following instructions below. Plant divided roots in a new section of the garden so the soil in the former location can recover.

Transplanting Peonies
If you are lucky enough to have mature peonies in your garden and want to transplant them or share them, the time to do this is in the fall when the plants are dormant. First, dig the new holes and amend the soil as necessary. Then to lift your established herbaceous peony, beginning at least eight inches from the base of the stem, loosen the plant from the soil with a large garden fork, work your way around the plant, and gently pry it from the ground.  The roots are brittle and can easily be broken. The peony can either be planted as is, or can be divided into several parts. Any time peonies are transplanted or divided, they take a few years to return to their previous grandeur.

Dividing Peonies
When dividing an herbaceous peony, wash the dirt off of the roots. Let the peony stand for a day so that it softens and becomes less brittle, you are letting the tuger pressure drop. The root has four parts: large tuberous roots, small fibrous roots, a connective crown and eyes at the top of the crown. Cut away the fibrous roots. Divide the plant into pieces by carefully cutting through the crown. Each piece should have 2-3 strong tuberous roots and 3-5 eyes in the top of the crown. Plant each herbaceous peony as far apart as the cultivar is tall according to the guidelines above.