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About Peonies

Wild Species and Ornamental Origins

Thirty two species of wild peonies are native from the Mediterranean region to eastern Asia, with two species endemic to western North America. The wild peony species are mostly herbaceous perennials, but some Chinese species are woody shrubs, mistakenly but perhaps permanently called 'tree peonies' in English. All are beautiful.
 
Herbaceous and 'tree' peonies have been domesticated for more than a millennium in China, and appreciation for them spread to Korea and Japan centuries ago. With the arrival of Europeans in China by the 1600s, there was a fascination with these treasured beauties. For whatever reasons, European introductions of ornamental Asian herbaceuos peonies initiated a multi-generational rage for peonies in Europe and North America, but there was much less engagement with the sophisticated tree peonies. Over time, both groups have become popular garden plants.
 

Peony Floral Forms

The American Peony Society recognizes six (6) flower forms for all types of peonies The key features are outlined below. The forms intergrade, but techinally every flower has to be placed in a form. The forms reconginzed by Chinese and Japanese conniseurs vary from the forms given here, especially once tree peonies are included. 

Click here for an excellent set of consice articles on peony floral forms.

To see the distribution of floral forms within the Peony Garden as of 2014, click here.

Click any image for a larger view

Single: Similar to the wild form of the peony with five or more guard petals arranged around the carpels and pollen-bearing stamens of the flower. This is the fundamental peony flower form.
 
 
 
 
Japanese: Five or more guard petals arranged around the carpels and stamens. Stamens are transformed into stamenoids which are similar to stamens in form and color but have a lumpy texture and thicker tissue that prevents them from shedding pollen. This form is the first in the series where the normally pollen-bearing stamens are transformed into distinctive petal-like tissue.
 
 
 
 
Anemone: The stamens of this flower are transformed into petaloids - small, narrow petals in the center of the flower - surrounded by the outer guard petals. This form is the next step in the transformation of stamens to distinctive petal-like tissue.
 
 
 
 
Bomb: The stamens of this flower are completely transformed into inner petals. These inner petals are narrower than the outer guard petals so that the flower looks like a sculpted ball of ice cream on a shallow bowl. A "bombe" is the name of this style of ice cream dessert. The bomb ends this series of stamen transformation.
 

 

Semi-double: Five or more outer guard petals with a center of smaller inner petals often decreasing in size as they near the center of the flower. Pollen-bearing stamens may be intermixed with petals or be present in the center of the flower. Occasional transfomation of stamens to petal-like structures. 
 
 
 
 
Double: Five or more outer guard petals with a center of stamens and carpels that have been more or less transformed into petals - creating the full body of the flower. Occasional stamens may be interspersed throughout the flower.
 
 
 

Kinds of Peonies at the Nichols Arboretum - Beyond Floral Forms

The Nichols Arboretum Peony Garden is home to historic herbaceous peony cultivars that were introduced into gardens throughout the nineteenth and first half of the twentieth century. Interest in peony breeding was intense during this time, producing a boom in the number of peonies introduced into the market.
 
Left: 'Postillion' by Saunders, 1941
 
Peony breeders are always trying to improve the peony by cross-pollinating one peony with another. Breeders are individually looking for their ideal balance of sturdier plants and different colors, forms, and foliage characteristics. Breeders also try to extend the bloom season by selecting for plants that bloom earlier or later than current cultivars. The peony garden represents 46 peony breeders. After World War II, the passion for peonies declined, reemerging again in the 1980s.
 
 
  • To see the range of years that the Nichols Arboretum historic herbaceous peonies were introduced click here.
  • To see the distribution of the national origin of historic herbaceous varieties present click here.
  • To see how many cultivars each of the 46 breeders introduced regardless of kind of peony, click here.

Peonies by breeder

 

Peony Flowers: season and color

Herbaceous peonies bloom at varying times throughout late spring and early summer. The earliest begin blooming in mid-May. The bloom is usually finished by the Summer Solstice, however on a particularly cool year blooms may continue into early July.
 
Click here to see the distribution of bloom time within the Nichols Arboretum Peony Garden.
 
Traditionally, herbaceous peonies come in four colors: white, blush, pink, and red. Through modern breeding, a greater range of colors has been achieved including coral, yellow, and patterned peonies. However, due to the historical nature of the peony garden, the peonies in this collection are within the narrower, traditional color range. To see the color distribution of the peonies click here.
 
 
Click the image on the left to see the different parts of the peony flower.