Glossary of Peony Terms

Peony Terminology Made Easy

Getting to Know Peony Talk

Terms-Where Science Mixes With the Market Place

Carpel, plumule, disk?  Like all plant groups, peonies (Paeonia) have their own descriptive terminology.  Knowing these terms can be helpful in better understanding all aspects of our favorite plant-the peony.

Many terms are freely used in the market place to describe the many and varied characteristics of peonies, but are equally used in scientific aspects.   But how are they important?  Often, the terms are unfamiliar to gardeners and can serve to help in the many decisions that are involved in growing, purchasing and enjoying this wonderful plant.

Example: In peonies, the vessels that contain the seeds are not called “pods,” but rather, carpels!  These finger-like structures are unique in the plant world and have been specifically named to recognize their characteristics.

*If you find a term that is missing or you are not familiar with, let us know, the APS would be glad to add to our glossary!

Peony Glossary (page under development)

Terms A-G



Meaning reproduction without sex.   This often refers to vegetative propagation.  Division, tissue culture and grafting all produce identical plants through asexual reproduction.  No pollen (male) or ovules (female) were involved to produce new plants.

Image:  Herbaceous peony division

axillary bud

A bud that grows from the axil of a leaf. An axil is the place in which the leaf is joined to the stem. These are sometimes referred to as secondary buds.



The basic thread-like structure that carries genes.

clone (clonal)

Genetically identical individuals.



Refers to peonies that contain two complete sets of chromosomes, one originating from each parent. Diploid is considered the basic configuration of chromosomes in most organisms.




The suspension of normal growth function by peony plants and seeds. This is often referred to as a resting state, but chemical changes are occuring in peonies during this period which are important to their growth.



Unit found on chromosomes which are transferred from a parent to offspring. Genes are the basic unit in heredity and are expressed as traits or may be held in a recessive state (no expression).

genetic compatibility


The joined product of stem to root, as often seen in available woody peonies.


Commonly used process to propagate woody peonies, in which a scion (stem) is usually joined to a herbaceous peony’s root to produce a graft.

guard petal(s)

Peony Glossary (page under development)

Terms H-M


Link to larger USDA Hardiness Zone Map

heal or healing

A term that describes a period of time in which a graft’s scion joins through cellular growth to a nurse root.  A period of 2 weeks at a temperature of approximately 80F, in damp conditions is generally viewed as optimal healing conditions.  Numerous methods and variation are used to attain proper healing.  See grafting article for further information.

herbaceous peony

Any peony that produces annual growth and contains no woody parts above the soil surface.

intersectional peony

See Itoh peony

Itoh peony


lutea hybrid

The name given to a group of woody peonies that originated from crosses of P. delavayi x P. suffruticosa.  At one time the yellow form of P. delavayi was classified and named P. lutea.  The lutea hybrids have the largest color variation of any group of peonies, P. delavayi being largely responsible.

Peony Glossary (page under development)

Terms N-S

nurse root

Sometimes referred to as understock.  A root used in the grafting procedure that serves as a temporary root system, until the scion or bud material produces ‘own roots’. Commonly used to propagate woody peonies.






A stem that includes buds used in grafting to join with a nurse root.

species peony

A group of similar individual peonies capable of reproduction in nature. These are often referred to as ‘wild’ or ‘wild botanic species’, as they occur in nature without human intervention in their life cycles.




Peony Glossary (page under development)

Terms T-Z

terminal bud


Tree Peony

See Woody Peony.


woody peony

Any peony that produces persistant perennial stems above the soil surface.  Often, incorrectly termed “Tree Peony”.

Additional Resources

Want to learn more? See below for a list of downloadable PDF resources.