Now Is the Time to Start Thinking About Peonies!

Categories Horticulture, Plant of the Month, This Month

By Lydia Wallis

Peonies can be documented as far back in history as Confucius (551 – 479 BC).  They have been revered for centuries and immortalized on textiles and in paintings.  They are truly one of my favorite flowers with their entrancing beauty and alluring fragrance. Their magnificent blooms enhance border gardens but can also stand alone and still have a stunning impact.  They are also effective grouped in mass plantings or in rows creating a low hedge. Peonies are unsurpassed in floral designs or as a single stem in a vase. Best of all, they exhibit a high degree of pest and disease resistance, including deer damage.

Peonies offer five distinct forms: Single, Semi-Double, Double, Japanese and Bomb.  They prefer a sunny, well drained location. Sandy soils produce more foliage and fewer flowers.  A clay soil produces slower growth but better flowers. Too much shade and plants become tall and leafy. Peonies should never be planted where a peony has been grown before unless the soil has been removed to a depth of 3’ and replaced, which is a lot of work!

Unless you have purchased your peony growing in a container, division and planting of bare root plants should be done only in the fall.  Dig a hole large enough to accommodate the root system and mix in compost about a foot deep at the base.  The peony eyes should be no more than 1”-2” below the surface of the soil with the eyes facing upward; the tubers will fall naturally into place.  If planted too deeply, they won’t bloom. Plants should be spaced 3’-4’ apart. Water them in the hole, fill with soil and tamp lightly and water again.  Once the ground has frozen, apply mulch the first winter.  

Once established, peonies are extremely drought tolerant.  However, if your peonies wilt from lack of moisture, give them a good soaking.  Deadhead as soon as the flowers fade. This prevents seed formation and allows the plant to put its energy back into the plant, rather than into producing seeds.  First year flowers are often not typical; like many plants, it takes two to three years for the peony to become established. 

If the ground has been properly enriched at planting time, fertilizer will not be necessary.

If it is needed, give them rose food and a light application of bone meal in the spring when the foliage is 6”-8” tall.  If manure is used it should be well rotted and kept from getting over the crown of the plant. The same goes for fertilizers.  Note that over fertilization may also reduce flowering.

Peonies seldom require division; some live as long as 100 years in the same location!  However, if you want to divide your plant or share it with friends, dig up the clump in September or October and carefully remove all soil without breaking the tubers. They are quite brittle.  Wash the tubers so that the eyes (growth buds) are clearly visible and trim away any tubers that have rotted. Slice through the clump with a knife, from crown downward dividing the plant into several pieces, each with several tubers and eyes.  Plant immediately.  

Botrytis is the most common disease problem and is most prevalent during wet seasons.  Careful sanitation and regular inspection of the plants with removal of any infected leaves, stems or buds are the best controls.  Look for young shoots that have rotted off at the base, foliage and stems that have turned black or developed a dense gray mold and blasted buds or blooms.  Herbaceous peony foliage should be cut back to the ground in September. All foliage, diseased and healthy, should be burned. This will prevent carry over of any disease spores that might be present.  Please do not place any peony foliage on your compost pile.

When selecting peonies, be sure to purchase them from a reputable dealer or nursery.  Any bargain will probably be a single tuber with one eye that will take longer to become established.  There was a time when peonies were either white, pink or rose colored. Today we have a choice of gorgeous colors including corals, yellows, green, red and even some stripes!  

If you haven’t tried one of the Itoh’s, Intersectional peonies, I urge you to do so.  Itoh’s are a cross between a tree peony and an herbaceous peony, first created by a Japanese horticulturist, Dr. Toichi Itoh.  They have large, long lasting blooms that do not require staking, with foliage that grows dense and healthy in full sun. You will not be disappointed.