Originally from China and Japan, peonies, with their big fluffy, fragrant flowers, add impact, drama, and color to any garden.
If you follow the basic guidelines in our planting guide, you will find that it is easy to grow perennial peonies. Better still, once they are established, they will keep on growing and flowering for decades.
But first things first, when is the best time to plant peonies? Generally, it’s best to plant bare-root peony tubers in the fall so they can become established during winter. In cooler climates, you can plant them in spring, but they are unlikely to flower for a couple of years. You can also plant seeds in fall, though they will only shoot in spring or summer.
PLANTING PEONIES IN DIFFERENT CLIMATES
Peonies prefer to be planted in the fall in most climates, although in colder areas, you can also plant successfully in spring. But it’s important to realize that since peonies bloom from late spring until early summer, planting times will impact when you will be rewarded with peony flowers.
There are many different varieties of peony, including herbaceous, bush peonies that die back in winter, tree peonies, and intersectional hybrids that are a cross between the other two types. Some are hardier than others and will survive lower temperatures in the winter months.
Generally, peonies are hardy enough for Zone 3 where the minimum average temperatures range from -30°F/-34°C to -40°F/-40°C and will grow well in the southern Zones 7 and 8.
In these regions, the minimum averages are 0°F/-18°C to 10°F/-12°C for Zone 7 and 10°F/-12°C to 20°F/-6°C in the milder Zone 8.
The National Weather Service National Oceanic and Atmospheric Administration has useful information about the Köppen climate classification system used in North America for more than a century.
In areas that experience a warm tropical climate, average temperatures are greater than 64°F/18°C in all months and the annual rainfall is more than 59 inches.
Because it’s so hot, it’s best to ensure that your peonies are planted in late fall. This will allow the roots to become established during the cooler winter months.
In dry climates, potential transpiration and evaporation is greater than the rainfall.
When you grow peonies in a dry climate the two most important factors are choosing varieties that will survive in this climate, and proper watering. Plant in the fall.
Winters are generally mild in a temperate climate, while summers are warm and humid. It gets very windy in winter, while thunderstorms are common in summer.
In temperate climates, peonies do best if planted in fall.
Cold in winter and cool to warm in summer, continental climate areas experience average temperatures of 50°F/10°C in mid-summer and less than -22°F/-30°C in mid-winter.
In continental climates, it is also best for peonies to be planted in the fall. Since this is a cooler climate, you can also plant in spring.
In polar climates, it’s cold throughout the year. The warmest temperature at any time of the year is commonly less than 50°F/10°C.
Depending on whether the area is in Zone 1 or 2, winter temperatures can drop below -50°F/-46°C or average between -40°F/-40°C to -50°F/-46°C.
Peonies love cold winters, so it’s worth trying to grow them, but plant in summer (mid-June).
CHOOSING PEONY SEEDS
The most popular way to plant peonies is from bare-root tubers with between three and five eyes or flower buds. However, peony seeds are available. It isn’t difficult to grow peonies from seed, but it will take at least three to five years for them to establish themselves.
Another factor to remember is that peonies don’t like being transplanted. So if you’re planning to grow your peony flowers from seed, try to ensure you choose the best possible site.
They like full sun and will usually bloom beautifully in areas that get between six and eight hours of sun a day.
WHICH PEONY SEEDS TO CHOOSE
First, you need to ascertain which varieties grow best in your climate. Seed packets provide information relating to the hardiness zones your peony flowers will do best in.
You must decide whether you are going to grow herbaceous peonies, intersectional peonies, or tree peonies. There is an enormous choice in terms of color, height, bloom times, and form, including singles, semi-doubles, and spiders.
There is also a multitude of heirloom favorites that provide gorgeous cut flowers.
Once your peonies are established, you can collect seeds from the pods of your plants. Just be aware that intersectional (Itoh) peonies don’t produce viable seeds because they are sterile. A few herbaceous hybrids and hybrid tree peonies are also infertile.
Bare-root peonies and seeds are available online and from garden centers and other outlets that stock plants.
HOW TO PLANT PEONY SEEDS
Whether you are planting peony seeds or bare-root stock, you need a garden bed that will drain well. Peonies need water throughout the growing season, but they don’t like waterlogged soil.
You can also plant the seeds in pots in the fall and then plant them out in the garden in early spring, once they have sprouted through the soil surface and begun to develop.
If you are planting commercially produced seeds they will be ready to plant as soon as the time is right. If you are going to harvest seeds, wait until the pods darken and crack open. The fresher the seeds, the more likely they are to sprout in the first spring.
Check the pH of the soil; it should be near 7.0. If it isn’t, you can add garden lime to the soil. You can also add compost if the soil is very sandy or needs nourishment.
PLANTING PEONY SEEDS VS TUBERS
Dig a hole or furrow and plant the seeds about two inches deep and one or two inches apart. In very cold areas you can cover with a loose layer of mulch, like shredded bark or pine needles. Remove the mulch in spring otherwise the plant will react as if it’s been planted too deep, and it won’t flower.
If you are planting bare-root tubers, dig and turn the soil to a depth of at least one foot. Plant them about three to four feet apart so there is good air circulation between the growing plants.
Make sure that the bare roots are about two inches below the surface of the soil. You mustn’t plant them deeper than this. They may grow well, but you may be rewarded with peony flowers.
PLANTING PEONIES IN POTS
Follow the same process you would if planting directly in a garden bed. Just be sure to dig a hole for tubers that is twice as wide as the root ball.
HOW TO WATER PEONIES
As soon as you have planted your peony seeds or tubers in well-drained soil, water them thoroughly. If you’ve planted them in pots, take extra care not to over-water them.
Peonies don’t need a lot of water. Water from early spring only if there is no rain for more than two weeks. You want to ensure that the two four to six inches of soil is moist during the growing season.
Continue watering in this way throughout summer, even when the flowers have died.
If you want to install an irrigation system rather than hand-watering your peonies, consider drip irrigation. It saves time and is also a good way to prevent fungal diseases like botrytis that affect the tubers, leaves, flower buds, and flowers of peonies.
HOW TO GROW PEONIES
All types of peonies grow well in moist, well-drained soil in full sun. Tree peonies, which are woodier and grow a lot taller, need a sheltered spot.
They should never be planted too deep and they should never be over-watered.
While we do recommend adding compost to the soil when you first plant your tree and herbaceous peonies, it’s not essential to amend the soil with fertilizer.
While it might make a difference, lots of peony farmers say they plant in the native soil, even if it is clay-based. Only fertilize pot peonies with a slow-release fertilizer.
It’s easy to grow peonies, but there is a little maintenance required. For instance, when flower heads die, remove (or deadhead) the blooms.
When herbaceous or bush plants start to die back, you should prune them. You don’t need to prune tree peonies.
We’ve said that peonies don’t like to be moved. If you need to transplant them, lift them carefully in the fall and replant them immediately.
You can also divide them at this point, as long as you keep three to five flower buds on each bare root.
Peonies are very hardy plants but they are susceptible to a few pests and viruses. Fungal diseases like botrytis can be a problem.
If you spot blackened or rotting stems and buds, cut off the areas that are affected and dispose of the debris in the trash.
WHAT IS THE BEST TIME TO PLANT PEONIES?
The best time to plant peonies throughout the U.S. is in the fall, from September to November.
However, there are areas of the country, including parts of California, Washington State, Oregon, and in the south, where gardeners plant peonies successfully in December.
While not common, there are even reports of bare-root peonies being planted in January and February.
There are lots of tips in the section Planting Peonies in Different Climates. Generally, they grow best in colder climates and frost isn’t a factor. In hot climates, it’s best to plant peonies in winter.
HOW LONG DOES IT TAKE FOR PEONY BULBS TO GROW?
Peony tubers, which are sometimes referred to as bulbs, will usually sprout in early spring if planted in the fall. If they are planted in spring, they will usually take a year to sprout and another year before they flower.
If you are growing peonies from seed, it will take anything from three to five years for the bulb or tuber to form.
Peonies have the most beautiful blooms and they make wonderful cut flowers that will last for weeks in a vase. They are easy to grow and, unlike most perennials, don’t need to be dug out and divided every few years. They will simply continue to grow and produce magnificent peony flowers for decades.
Our 2021 planting guide is full of tips that will help you to plant and grow bush, tree, or intersectional hybrid peonies in your home garden. We have included advice for growing them from seeds and bare-root tubers, together with invaluable information about when to plant.
There is minimal effort involved when it comes to growing peony flowers. And whether you want cut flowers or a colorful show in your garden, you are sure to be rewarded.