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Botanical terms have precise meanings. Readers looking for definitions and examples of specific botanical terms may find Wikipedia useful, as well as the following on-line glossaries. If a term is causing confusion and is not in the on-line glossaries, Wikipedia, or this Glossary page, please contact us.


Peony Database Glossary

Common English words may have different meanings for peony specialists, and the nuances may shift over time. This is why a reference collection so important - presumably the plant should be consistent if viewed under the same circumstances (light, time of day, etc.) To help with clear communication among all users, each term has:

  • A short definition. 
  • An explanation to help clarify the term and, if appropriate, its historical as well as contemporary use. For deeper understanding of the historical terms, please see our Code Breaking page.


APS Rating (American Peony Society Rating)  A decimal scoring system to compare and rank peony flowers for relative perfection. It was developed in the early 20th Century as a 10-point system where higher scores were better. The formal rating ended in the 1930s but was likely influential at the time when the Nichols Arboretum peony collection was being assembled. Dr. Upjohn was an active point-scorer of his own peonies at Brook Lodge in the early 20th century, so the quest for excellence was clearly important to him - see Peony Garden History.
Breeder The person who made and selected the cultivar. Usually, the breeder also names the cultivar. The breeder may or may not have been the person or company that introduced the cultivar to the trade. 
Color - Actual  For comparative purposes, 'actual color' is the hue of the top (apical) flower the day it opens. This has to be determined in the shade - not direct sunlight and not under artificial light. This color is our staff and expert's judgment using a 'normal' color term understood by the public. Please note that peony flower colors may change subtly to dramatically from bud opening to end of bloom and that only the top flower the day it opens is considered, not the floral display as a whole. Once open, peony flowers often display complex shades and sheens that are difficult to describe - this is part of their appeal. (see Color - Historical). 
Color - Historical The color description used when introduced as well as in the literature. Color terms were not standardized and are best taken as a descriptive range rather than an absolute unless listed as 'pure' or an equivalent term. It seems likely that some color terms reflected the writer's flower repetoire or commerical objective - thus 'red' may have been the reddest seen to date, rather than a specific color value. Very few peonies are referred to as 'blue' and even in our times, under diffuse natural light conditions as the flower opens, one can imagine that a faint blue tone could be perceived by keen enthusiasts.
Cultivar A cultivated variety or named selection of a plant. The precision of the term has changed as biology,  genetics, and patent law developed. Modern cultivars are often genetically identical. These are clones of one mother plant. Peony cultivars introduced years ago may be from sibling seeds of a particular hybrid cross. It would be if as fraternal twins were both named ‘Pat’ - both are authentic and both are correctly named ‘Pat’.
Cultivar Group  A set of cultivars that have key features in common. There is currently little diversity in cultivar groups in the historic peonies at the Nichols Arboretum. This data field will be more robust as the collection is rejunvenated and expanded into diverse tree peonies and intersectional hybrids.
Fragrance - Breeder  The scent description when introduced. This is the fragrance concept intended at the time the plant was new to the trade.
Fragrance - Historical  Fragrance descriptions in references after the cultivar was introduced. Fragrance was sometimes described and sometimes simply ranked: X is present, XX is strong. No ranking presumably means fragrance was absent, not consistent, or perhaps even malodorous.
Fragrance - MBGNA Staff  Fragrance as percived by our staff. Fragrance is best experienced as a flower opens and before the heat of the day. Peony fragrances are complex, can degrade quickly in the heat, and can be perceived quite differently by each visitor.
Historical Significance  Published critical opinions and detailed observations from experienced peony growers and judges are presented here. See also the Code Breaking page! All references are courtesy of The American Peony Society and used with permission.
Identification Correctly naming a plant. Verification Level (see below) is the ‘Gold Standard’ assessment of identification.
Season  Peonies are often listed as early, mid-, or late bloomers. These terms are relative as bloom time and duration is strongly affected by the weather. It is true that some cultivars (genotypes) do tend to bloom earlier than others, but the information listed here is from published lists rather than our own data.
Verification Level The degree of confidence experts have that the name is correct. Verification requires historical documentation, knowledgeable people (preferably a team with overlapping experience and specialties), and the plant-in-question with the distinguishing features at their peak. For peony cultivars, the distinguishing features require an apical bud on the first day it bursts into bloom. Peony cultivar verification cannot be done by photographs alone. Our verified photographs are a tool to help with initial identification.
For this project, verification has been done plant-by-plant with teams of peony experts: our Peony Advisory Board. Some plants have been reviewed more than one year. Details of which experts were on which team each year is in the detailed documents (not currently on-line). In addition, a 3-page data sheet was partially completed for many of the plants to build a consistent character set for future use. The Verification Levels are:
1A. Confirmed: Authoritative  Members of the verification team sight-recognize the cultivar based on their knowledge and have absolutely no doubt this identification is correct.
1B. Confirmed: Consistent with Description  Members of the verification team are not personally familiar with the cultivar, and the historical descriptions fit the specimen without doubt.
1C. Confirmed: Very Likely Correct  Members of the verification team are not personally familiar with the cultivar, and the historical descriptions fit the specimen reasonably well.
1D. Confirmed: Maybe but a poor specimen/year to verify  Members of the verification team are not personally familiar with the cultivar and the specimen could fit the historical descriptions, but the plant is not blooming in a typical manner. This may be due to weak flowering (which may be atypical), use of side flowers (not an apical flower), flower not fully expanding due to the weather, flower past its prime etc.
1E. Presumed Correct: Recent materials from knowledgeable sources  Plants acquired after the 2009-2012 major verification effort and needing confirmation in a future phase. Post 2012 plants from less knowledgeable sources are coded '3A Not Evaluated.'
2A. Uncertain: Not Consistent with Description  The specimen has non-trivial differences with the historical description but is not completely wrong. Since some historic cultivars were seed-siblings, exact fit to description may not be realistic.
2B. Unknown: Unknown After Review  The identity of the plant is unknown: members of the verification team are not familiar with it and it does not fit the historical descriptions for cultivars it has been claimed to be, including any that were once planted in this location.
3A. Not Evaluated  The plant has not been verified. There may be several reasons.
     For plants present before 2012, it is usually due to lack of bloom. The plant may not be healthy enough to bloom, may be an erratic bloomer, or may bloom so late in the season that the buds fail to open with the sudden onset of hot, dry winds.
     For plants acquired after 2012, it means the plant should be reviewed by competent experts. (Compare with 1E. Presumed Correct)