I do not like the term expert, but I can share with you my methods of growing peonies, and I have grown thousands successfully. I am always learning something new every year, and look forward to what my field can teach me this year. Peonies are a relatively easy perennial to add to your garden, if you follow the correct planting guide.
There are three types of peonies, woody, intersectional and herbaceous. Below is instructions for herbaceous, we'll publish information for the other two at a later date. Herbaceous peonies are our common garden varieties, and what can be found in our 2023 catalogue.
We tend the hear that herbaceous peonies do not like to be moved. You might kill them transplanting. They are fussy. I do not find this to be true, they just like to be treated in a certain way.
Peony Growth Cycle
Herbaceous peonies grow new stems every year, and emerge in the early spring. They bloom in late spring, with blooms lasting between 1-2 weeks.
After they finish bloom, they start seed production. Seeds are ready to be picked in late summer, early fall. Not all herbaceous peonies are fertile however, and seeds within pods might not form depending on the genetics of the plant.
Mid summer, they begin to produce eyes, under the soil, on the crown of the plant, which are the following year's stem growth.
The old stems die back in the fall and the plant goes into dormancy. It restarts its life cycle in early spring the following year.
A peony root's anatomy consists of tuberous roots, and fibrous roots. The fibrous roots are where the nutrients and water are taken in by the plant. They are the fine hairy looking roots. The tuberous roots are what produces the plant. They are the thicker, chunkier roots.
You'll also find the crown, where the eyes form. It is the top of the root. The eyes form on the crown, in this photo they are pink, they can also be white depending on the cultivar.
Each cultivar's root forms slightly difference, ranging from size, and general formation. The later in the fall season, the larger the eyes become.
When Should You Plant a Peony
This is probably the most confusing aspect of peony culture. While spring is the most common time to plant your garden, it's not the best time to plant a peony. The best time to plant a peony is in its dormancy phase, in the fall. This way we are not disturbing it's growth cycle.
When can you break this rule? If you buy a potted peony plant from a garden center, this can be transplanted at any time. Spring planted bare roots are also acceptable to plant, if you live in a climate that has a long cool spring. Where I am in zone 5b, our spring gets hot too quickly, and spring planted peonies are not as successful.
A question I receive often is, "should I store my bare root in the fridge until fall to plant" or "should I plant in a pot in the spring and transplant in the fall". The answer is the same for both- no. If you have a bare root, plant it in the ground as soon as you obtain it. It will get established faster if you allow it to grow in it's permanent spot. However, do your research and buy from producers that can send you a root within proper time to plant it.
Most commercial peony growers send out their roots in time for proper planting in the fall. We ship plants starting in the first week of September, and plant our own field in October. As long as you can stick your spade in the ground (ie the soil is not frozen), it's not too late to plant.
We have planted in snow squalls in November. When ordering roots from overseas, arrival times cannot always be predicted. Planting in November, and even early December in most climates in Canada is perfectly fine. If the ground is not frozen, then you can plant.
I understand it is confusing when box stores have peony roots for sale in the spring, but know this isn't not the best planting practice to have a successful peony, and box stores are not peony specialists.
How to plant a peony
Now that we have the time of year determined, here's a quick planting guide.
Soil prep
Here's a quick rundown of what we do in our commerical field, which does not really apply to a residential garden. We till our rows in the fall for the following falls planting after laying down 2 inches of compost. We add radishes as a cover crop, which makes further breaks down compaction and is a nematode trap. In the spring, we till the smelly rashishes in, and then solarize the rows. We may plant dahlias in some of the rows if spacing is an issue. We plant mid October and add 1-2 inches on wood chips on top.
In the garden, I would recommend amending the soil with a bit of compost, and maybe a dash of bone meal. Peonies are not heavy eaters, so more fertilizer is not really needed.
Watering
Now this is an important one - THERE IS NO NEED TO WATER RIGHT AFTER PLANTING
I stress this as it could easily be why your peony doesn't live. Overwatering, prior to a peony establishing it's feeder roots (those fibrous roots) will cause the peony to rot. The water cannot be absorbed by the peony without those fibrous roots. Peonies are slightly drought resistant, so plant it and walk away, let the rain water it.
Spacing and depth
The main issues I encounter when planting is depth. the eyes should be 1-2 inches below the soil line. What happens in the winter, is sometimes the frost line will heave the root out of the soil. To fix this, I recommend putting a good dose of mulch on top to protect it in case it gets heaved out. Once the roots have established themselves and bind themselves firmly in the ground, this no longer becomes an issue.
Peonies will become large in time, it's best to give them 2 ft diameter spacing. In year one, they won't require all that room, but you'll be happy to made room for it by year 3. Fill the space with annuals while you wait for your peony to mature.
Sun requirements
6-8 hours of sun is the minimum requirement for herbaceous peonies. While there are some exceptions, like the Early Windflower, and Late Windflower and some species, who can handle more shade, they really prefer a sunny spot. If planted in a shadier place, they tend to flower less, and become long stemmed, as they are reaching for sunlight.
Final Notes
I receive the occasional email in the spring that a peony has yet to emerge. I find by poking around the soil with a finger you can uncover some lovely eyes. Peonies require PATIENCE. They are also living plants, there is a possibility that your root does not survive the winter. Like any plant, they could not make it. This is a gardening reality that one must accept before purchasing expensive roots. It is not the fault of the farmer, nor even sometimes the gardener, just facts of life.
I wish you all success in your gardening journey, and I am always here to answer questions.