Peony Cultivars Explained: Types, Registry, and How to Choose
A peony cultivar is a named, cultivated selection—distinct from a wild species—and the fastest way to identify one is through the American Peony Society's Peony Registry, the official international database listing more than 7,000 peony cultivars. If you are choosing plants for a garden, start by deciding which of the four main cultivar groups fits your climate and space: herbaceous, Itoh, woody, or species peonies. The sections below explain how those groups differ, how cultivar names work, and how to narrow the registry down to plants worth buying.
Cultivar vs. species: what the words mean
A species peony is a naturally occurring wild plant, such as the various Paeonia species listed on the American Peony Society site under "Species Peonies." A cultivar is a plant selected or bred by people, given a registered name, and propagated to stay true to that name.
Two practical consequences follow:
- Cultivar names are written in single quotes, e.g. a named garden selection, while species names are written in italics without quotes.
- Because cultivars are propagated vegetatively (division, grafting), a purchased cultivar should match the registered description. Seed-grown plants, including those from the Society's Seed Distribution Program, do not.
The four main cultivar groups
The American Peony Society organizes its Learn section around four groups. They differ in how they grow, how they die back, and how much cold they need.
| Group | Growth habit | Winter behavior | Notes for gardeners |
|---|---|---|---|
| Herbaceous peonies | Soft stems from the ground each year | Top growth dies back; roots overwinter | The classic garden peony; needs winter chill |
| Itoh peonies | Intersectional hybrids (herbaceous × woody) | Dies back like herbaceous types | Valued for extended bloom and strong stems |
| Woody peonies | Persistent woody framework | Stems remain; buds break in spring | Also called tree peonies; slower to establish |
| Species peonies | Wild-type forms | Varies by species | Useful for collectors and species-appropriate sites |
If you garden in a warm-winter climate, the herbaceous and Itoh groups are the ones most likely to disappoint, because they generally depend on a cold dormant period. Woody and some species peonies behave differently, but check the individual registry entry rather than assuming.
How cultivar names and registration work
The Society maintains a Registration Overview, Registration Procedures, and a New Cultivar Submission process, which together mean new cultivar names are formally registered rather than casually invented. For a buyer, this matters because:
- A registered name is a stable identifier. Two nurseries selling the same name should be selling the same plant.
- The Peony Registry is described by the Society as "The Official International Database with More Than 7,000 Peony Cultivars," so it is the reference point when a name is unfamiliar or spelled inconsistently.
- Registration does not by itself mean a cultivar is widely available or suited to your garden—it confirms identity, not performance.
How to choose a cultivar for your garden
Work through these filters in order, using registry entries and the Society's Learn pages (Peony Growing and Care, Hybridizing, Propagating) as your reference:
- Confirm the group. Decide herbaceous, Itoh, woody, or species based on your winter climate and how much permanent structure you want in the border.
- Check bloom timing. The Society runs a Bloom Date Project, which is the relevant resource if you want to sequence flowering or avoid a single short season.
- Match color and form to the site. Registry records carry the descriptive detail; use them rather than catalog photos alone.
- Check height and spread against the space you actually have, especially for woody peonies that keep their framework year-round.
- Verify the name before buying. Cross-check the exact cultivar name in the registry, then look for it through the Society's Vendor Listings.
- Ask about local performance. The Reference Garden Program and Peony Societies listings point to plantings and groups where you can see cultivars growing under conditions closer to yours.
Where to find reliable information and plants
- Peony Registry — the official cultivar database, the first stop for any name.
- Vendor Listings — nurseries and suppliers listed by the Society.
- Bookstore and The Bulletin — longer-form reference material and Society publications.
- Reference Garden Program — gardens where peonies are grown and observed.
- Peony Societies — regional groups, useful for climate-specific advice.
- Seed Distribution Program — note that seed orders are shown as closed in the current site listing, and seed-grown plants will not reproduce a cultivar's exact characteristics.
Some Society resources sit behind a member login or member portal, and membership is handled through an Options & Pricing page with separate purchase and gift subscription paths. Treat access terms as stated on those pages rather than assumed.
Common sticking points
- Buying an unregistered or mislabeled name. If it is not in the registry, you cannot verify what you are getting.
- Assuming all peonies need the same conditions. The four groups do not behave alike in winter or in establishment speed.
- Choosing from photos only. Bloom color shifts with light and stage; registry descriptions and reference gardens are more dependable.
- Expecting seed to reproduce a cultivar. It will not—use division or grafted stock for named plants.
Start with the registry to confirm the name, then use the group, bloom timing, and vendor listings to decide whether that cultivar belongs in your garden.