Peonies Care Guide & Growing Tips

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Peonies: Overview And History

The modern peony is the result of many years of devotion and effort on the part of plant breeders. Peonies have been cultivated in China for more than 2,000 years, not only for it’s flowers but for it’s roots, which were used for food and medicine.

According to mythology, he received the first peony on Mount Olympus from the hands of Leto.

In Praise of the Peony

Present day gardeners are inclined to take peonies for granted.

Is this because they are so common?

The fact that they are so common tends to emphasize their many worth-while qualities. Peonies are hardy, permanant, very easy to grow and enjoy freedom from pests for the most part.

The varieties available are very diverse in flower form and colour.

Peonies also rank high as cut flowers; they last a very long time in a vase.

Some horticulturists consider interest in peonies to be on the wane after a burst of breeding activity in the late-80s. The fact remains, their potentiality for further improvement and diversity seems inexhaustable, and in the last few years, a few new varieties have come along that eclipse even some of the classics in form and colour.

Often overlooked, one of the finest features of peonies is the fabulous fall colour they provide.

If grown in sun, peonies leaves turn from green to burgundy in a matter of a week. Planted among fall-flowering perennials, such as Echinacea purpurea (the purple cone flower) and Eupatorum purpureum, they come into their own once again!

Guidlines For Growing Peonies

Soil

Rich, friable garden soil is best.

Heavy soil is fine providing it’s well-drained. Some form of organic matter, such as well-rotted manure or leafmold can be added to make it more friable.

Sandy soil is OK as long as fertility is maintained. Manure is good for this too but many gardeners get more specific and say that ‘horse apples’ are best.

Peonies prefer a pH of 6.0 to 7.5.

Location

Peonies flower best when exposed to full sunlight, although partial shade can produce satisfactory results. Like a rose, at least 5 hours of strong sunlight per day is a good rule of thumb.

Because of the need to stake them, it’s also best to keep them out of high winds.

Moisture

Moderately moist soil is best.

Planting near trees or shrubs is not recommended as there is too much competition for soil moisture. If your spring is dry, irrigate to aid in the development of strong stems. Dry summers?

Irrigate to produce big flower buds.

Peonies are not drought tolerant.

Preparing The Soil

Spade, or loosen, the soil to a depth of 12 to 18 inches.

Thoroughly work in compost or well-rotted manure. Include 1 handful of rock phosphate and/or bone meal per each peony to be planted.

If the soil is acid, apply some limestone several weeks before planting.

When To Plant  

Peonies are available in pots throughout the spring and summer, and those can be planted as soon as they are brought home. If you are working from divisions, see the division section.

How Deep?

The most common reason for peonies not blooming is that they have been planted at the incorrect depth. There is so much confusion over this topic. It should be clear that the crown of the plant should be 1 to 2 inches below the soil surface. If you purchase one in a pot, be absolutely sure to check the depth of the crown before you plant it.

Don’t take it for granted that the nursery people knew what they were doing when they planted it.

Disbudding

Size and quality of flowers is improved by disbudding.

This is great if you intend to enter your flowers in a competition or cut them for use indoors.

Each peony stem usually has 5 to 7 flowers. In disbudding, you remove all but the top bud, as soon as the little side-buds are produced. Don’t leave it too long or you will defeat the purpose. All the energy that was to go to 5 to 7 flowers is now reserved for that one bloom.

Often disbudding provides amazing results.

Cutting

Cut flower stems containing buds which are just starting to open, preferably in the early morning. Be sure to leave 3 to 4 leaves at the base of the flower stem for the plant.

Supporting The Stems

The peony at right looks healthy enough, but it is pretty clear that it’s falling over. Support peonies with special, circular ‘peony rings’, tomato cages, or individual garden stakes.

In the example given, a large tomato cage, inserted into the ground as the shoots are extending in spring, would have done the trick. It is not always necessary to stake, and floppiness of stems has alot to do with their culture and the variety you select.

If you have the time, shake the water out of your peony flowers after the rain. This will lighten the load and therefore help prevent toppling.

Planting where wind will not speed by helps too.

Deadheading

It’s best to pick off dead flowers before all their petals fall to the ground, because a build up of petals around the base of the plant can become host to several pathogens which will in turn harm your peony.

One example is botrytis blight.

You can read more about that below in the PESTS section.

Deadheading also prevents seeds from forming, which costs the plant energy that is better put towards making strong roots.

Cleaning Up

Leave the foliage on your peonies until it has been killed by hard frosts — remember, the fall colours can be very attractive. When it is totally brown or black or withered, cut it off at a few inches above ground level.

Don’t wait til spring! Clean up in fall.

Dividing

Peonies will usually require division every 5 to 8 years, although if you want to increase the number of peonies in your garden, you can usually divide after only 3 years in the garden.

Dividing does disturb the plant and can affect blooming next year, so it’s usually best to let them be until they actually require division. Divide peonies about 2 months before the ground freezes, after leaves have become coloured by autumn and are just beginning to die back.

Dig up the clumps carefully. Then wash off the soil.

With a sharp knife, cut each clump, though the crown, into several peices. Each division should have several plump buds, which in the fall would be about 2 cm (1/2 an inch) long.

Don’t get greedy with the amount of divisions you make off one clump.

If the divisons are too small, it may take 2 to 3 years before full vigour is acheived and flowering occurs.

Reversion

Very old peonies sometimes revert to single flower forms, or fail to bloom altogether. If your peony has gone from double petalled to single, divide it in the fall and it will likely become double again.

Winter Care

During their first winter, peonies should be mulched to prevent them from being heaved out of the ground by frosts. After they are well-established, no protection will be necessary.

Common Pests:

  • ANTS – ants don’t eat peony buds. They feed on the sweet syrup secreted by developing buds, and do absolutely no damage. One old-wives tale says that ants are required before a peony will open, but this is not founded in science. On the down side, ants can spread the following disease.
  • BOTRYTIS – This can cause peony buds to dry up without developing into blossoms. The plants seem disease-free other than this. The best preventative is good fall cleanup and cleanup of fallen blossoms, including blossoms from plants other than peonies. Growing peonies under fruit trees can sometimes be difficult because this disease likes both plants so much. Spraying with bordeaux mixture or copper helps, followed by removal of all affected buds and leaves. If a neighbouring fruit tree is causing a problem, rake up the petals. Also, don’t forget to spray the tree with a dormant oil while the tree has no leaves (ie: dormant). In mild winter areas, you can spray dormant oil anytime. In cold winter areas, spray fruit trees in fall just as the leaves have fallen. Do the same in early spring, before the flower buds break.
  • ROOT DISEASES – If the leaves of your peony turn brown at the edges in mid-summer, either the plant is too dry or they have a root disease. Dig up and clean thoroughly in fall. Replant in a different spot. If problem persists, dispose of the plant.