When and How to Divide Peonies

All Peony types should be divided in fall after flowering, well before the first frost hits. I dig up the entire plant and cut the large roots into sections with at least three healthy pink eyes per division. Then, replant into well-draining soil in a sunny spot and wait for them to re-emerge in spring. Follow this guide to find out when and how to divide Peonies.

Reasons to Divide a Peony

Some perennial plants require dividing after growing in the same space for a long time. They may become overcrowded or grow better when separated and given a bit more room to breathe.

Peonies do not fall under this category. Most varieties spread three feet wide and won’t go further than that, never taking over any beds or creeping into unwelcome spaces.

In fact, they are so happy in their existing spots that they can live for well over 50 years without dividing, potentially outliving their owners.

But that doesn’t mean there are no reasons to divide.

Moving

If you’ve invested time and effort into growing your Peonies, you don’t want to leave them behind if you move to a new house. Luckily, you don’t have to. You can simply dig up the crowns and take the plants to replant in your new garden.

Even if you’re sticking with the same garden, you may want to move your Peonies to a new part of the garden or spread them across different beds. Division is the perfect way to add variety without compromising on care for those who frequently change up their garden design.

Propagating

Gardeners with one or two Peony plants may struggle to avoid growing even more. But, these plants can be pretty pricey, especially for sought-after and established cultivars.

Instead, you can double your Peony stock by propagating. Propagating by division is the simplest method and yields strong, healthy plants that match the genetics of the original cultivar. It is typically safer than propagating from seed, leading to unpredictable results (and plants).

Depending on the plant’s maturity, you can get at least one but potentially several divisions to plant out. Over time, these will grow into fully-fledged Peonies that can be further propagated to grow an entire field of your favorite plants.

Health

Like all plants, peonies require specific growing conditions and care to produce flowers and return again year after year. If your Peony is not flowering or growing correctly, dividing and moving the plant can resolve the problem and make the plants vigorous growers again.

Light is usually the number one reason to move regarding care. Herbaceous Peonies that don’t get a full day of sun will flower very little, if at all. Dividing and moving the plants to a better area will improve growth and flowering immensely.

Soil is another crucial factor, like well-draining, slightly acidic soil. If the soil contains too much clay or becomes compacted, it can affect the roots and kill the plant.

Pulling up the plants, dividing, and either amending the soil or moving the plants to an area with better soil will give the Peonies the foundation they need to produce their stunning flowers.

When To Divide a Peony

Some perennials are divided in spring before flowering, but this is not true for Peonies. They will take far longer to establish and flower if pulled at this time.

No matter which Peony type you are growing – herbaceous, tree, or Itoh – or for what reason you’re dividing, division should be done in the fall. Late summer is also suitable after the plants have finished blooming.

Peonies need a few weeks to establish in their new homes before the first frost hits. Check your local weather resources to determine the first frost date in the fall and count back 4-6 weeks. This will give you the ideal window for division.

How To Divide A Peony Plant

Dividing Peonies is a beginner-friendly task. They are resilient plants that don’t mind rough handling when being pulled or cut.

Follow these steps to divide your Peony in late summer or early fall:

• Cut back the stems back to just above the ground. This clears the leaves to make the roots easier to see but leaves you some of the stem to make pulling the entire plant at one time easier.
• With a large spade, dig into and loosen the soil around the plant at the point where the leaf spread ends. This will ensure you lift the entire plant without risking severe damage to any roots.
• Dig straight down and lift upwards towards the center of the plant to remove the shallow root system. Once loose, pull out the ground using the remaining parts of the stems.
• Wash all remaining soil off the roots to be clean and visible. They can hold on to dirt, so use a high-powered hose or brush to clean them.
• Identify sections of the roots with at least three buds or eyes. They should be pink in color and clustered close to old stems. The more eyes the root has, the more vigorous the plant will grow in the first year.
• Cut into the thick roots with a sharp knife, separating the sections into as many as the plant allows. Aim for around 5-6 eyes per division for the healthiest start.
• Leave the root divisions dry for a few days before planting to form callouses. This will limit the potential for disease and rotting when planted.

How to Plant

With your divisions gathered, you are ready to replant. Identify the perfect spot before you get started to avoid having to move the plant again later on.

Spacing and Depth

Your Peony’s spacing will depend on the specific variety you have chosen.

Herbaceous Peonies typically have a maximum spread of around three feet. Therefore, they should be the same distance apart from the nearest plant. Tree and intersectional Peonies follow the same principle but differ in size. Check the label of your chosen variety and space accordingly.

Depth is far more critical than spacing when it comes to Peonies. If planted at the wrong depth, these plants will struggle to grow and are unlikely to flower, ruining the effort of division from the start.

Herbaceous and intersectional Peonies should be buried 1-2 inches below the soil surface. Tree peonies can be planted slightly deeper, around 3 inches below the surface. Peonies planted too deeply will not flower, so getting these measurements right from the get-go is vital.

Soil

Peonies are not thirsty plants and prefer soil that dries out before the next watering. Their thick roots and crown cannot be left to sit in water for long periods, or they will quickly experience rot.

Therefore, the soil must be loose, well-draining, and nutrient-rich to allow these plants to thrive. Rich loam is the goal, but you can also amend light clay soils with plenty of compost before planting to improve conditions.

The soil should also be slightly acidic with a pH just below 7.

Light

The amount of light your plant requires depends mainly on type and variety.

Herbaceous and Itoh Peonies thrive in full sun and need direct light between 6-8 hours daily. Some varieties can handle shadier spots (like ‘Shirley Temple’). Check your variety for specifics before planting.

Tree Peonies also appreciate bright light but need to be protected from intense afternoon sun when flowering to extend the life of the blooms. An east-facing area of the garden is preferred. This will provide plenty of direct morning sun, with some shading in the afternoons behind a wall or tree.

Post Dividing Care

Watering

Water your Peonies immediately after planting to allow the roots to establish. After this initial period, they won’t require much watering over autumn and winter and can typically live off rainwater in suitable growing regions.

It’s vital to prevent the soil from becoming waterlogged after dividing. As the plant doesn’t take up much water without any leaves or buds, the roots don’t need much moisture and can start to rot if overwatered.

Avoid planting your Peonies in garden areas where water naturally runs or settles. The right amount of light will also speed up evaporation, preventing rotting.

Fertilizing

If the soil is amended with high-quality compost, your Peonies won’t need much fertilizing when planting. Ensure you mix it well into the soil for even distribution.

If you want to boost your peonies in spring before their first flowering, feed with a 10-20-20 fertilizer to promote blooming and vigorous growth. Add fertilizer to the soil around the crown rather than directly on the crown itself, as this can lead to fertilizer burn.

Key Considerations

Dividing is not tricky, but a few technical concerns can get in the way of your success. Stick to these essential rules to make sure you get dividing right.

• Always divide in fall – never spring – for vigorous, healthy plants (for more, see our in-depth guide to the peony season).
• Leave at least three eyes on each division, but preferably five or six for the best results.
• Disinfect the knife before starting with a 5% bleach solution to prevent the spread of disease.
• Don’t plant herbaceous or Itoh Peonies deeper than 2 inches. Planting too deep will prevent flowering and stunt growth.
• After planting, water allows the roots to establish themselves in their new homes.

Wrapping Up

Those wanting more Peonies than they can reasonably purchase should try dividing. When done correctly, you can produce even more blooming plants at no extra cost.