Winter Peony Care Tips Every Beginner Needs

Did you know that peonies actually need and like winter? Well, we all know they are cold hardy flowering plants, and in fact, they need to go dormant or “to sleep” to come back strong and willing to blossom profusely next year. In fact, it’s harder to grow a peony in hot regions than it is in places where temperatures drop to super-freezing! But they still need a little help to get through these months safe and sound…

And this is exactly what we are about to see: what care your peonies need to get through winter!

Why Do Peonies Need Winter?

As we said, peonies need winter, and cold temperatures, to go into dormancy and rest, so they can have the energy to grow new leaves and then blossoms next year. But how long? Well, they need between 500 and 1,000 chilling hours, which, if you divide them by 24, you get 20 to about 40 days of “cool”.

But what is cool? Here the problem is not “how low the weather gets”, they can withstand temperatures as low as -40°F (which, incidentally, is also -40°C), so, USDA zone 3. This means that they can grow in Bethel, Alaska! Just think that Toronto is zone 5, and you’ll see that our flowering protagonist can grow well in large parts of Canada…

The problem is that peonies need time under 40°F (4.4°C), and ideally to 30°F (-1.1°C), and this is what we call chilling hours.

Also, peonies will not mind a long cold season, but they will struggle if it is short.

So, looking after peonies in winter really depends on where you live. And on the type of peony you are growing in your garden.

Types of Peonies and Winter Care

There are three types of peonies, and they need a different treatment to prepare them for winter.

• Herbaceous peonies, which are perennial shrubs; you need to cut them back in late October or early November (the beginning of winter, depending on where you live).
• Tree peonies, which are deciduous, and they only need a small trim in fall.
• Intersectional peonies, also called Itoh, from the name of their first breeder; these too need a small pruning, better done after frost, so, when winter has actually begun.

So, we’ll look at pruning in detail soon, but first, what winter care do all peonies need?

1: Water Deeply Before Winter Comes

If fall is wet, your peonies will have water deep in the ground, and why is this helpful? Because frozen soil is not humid! They cannot access water when it is ice… And deep irrigation also promotes deep roots.

So, make sure that either the weather or you water peonies deeply before winter comes.

2: Careful! Mulching Peonies for Winter Isn’t Always a Good Idea!

If you live in a cold climate area, where winters can be harsh (from USDA zone 5 down) it is a good idea to mulch your peonies or replenish it if you had already laid it. Apply 2 to 3 inches (5.0 to 7.5 cm), it will keep the soil humid, fertile and it will avoid sudden changes of temperatures. Yes, Paeonia is a very cold hardy plant, but no variety likes quick excursions.

Avoid mulching close to the stems; leave them free or they may rot.

Now, mulching peonies in winter is not necessary, especially in warm climates; actually, it could be counterproductive, as they need cold soil.  If you live in USDA zones 6 or above, I would suggest you do the opposite, so, remove mulching from the base of your Paeonia plants!

And then, as winter comes to a close, and spring comes, remove the mulch by degrees around the base of your peonies. Leave the buds free to grow, and do it slowly, so, again, they don’t get sudden changes in growing conditions.

3: Mind the Peonies’ Eyes!

By late fall and early winter, peonies (especially herbaceous ones) will have new “eyes” or buds, at the very base, just at the top of the roots. These need to be protected over the cold season, so, leave them underground, or, if you see them at surface level or above, cover them with 2 inches (5.0 cm) of soil.

4: Remove All Wet and Rotting Leaves from Around Your Peonies

Keep cleaning at the base of the peonies, making sure that there are no wet and rotting leaves at their base; these will host molds, fungi and other diseases. Which leads us to the next point…

5: Cut Back Herbaceous Peonies

As soon as the leaves brown (or they may even turn to black), you must cut back herbaceous peonies to ground level. This will usually occur with the first frost, so, at the beginning of winter. You can do it a few days before or after, but keep a window in your gardening calendar to do this. And it’s very simple…

• Use sterile blades, loppers are ideal for this job, but you can use secateurs for pruning shears if you wish.
• Cut all the stems back to about 1 inch (2.5 cm) above ground level.
• Sterilize the blades before each plant, so you don’t risk spreading diseases.
• Remove all you have cut; don’t leave it there to rot.

Also, avoid removing browning leaves in fall, allow them to drop naturally; then you will cut down the whole plant.

6: How to Prune Tree Peonies

Tree peonies require a totally different type of pruning, much lighter than with herbaceous varieties, and the timing is different too: late winter is ideal, or early spring would be fine too.

• Use sterilized blades, pruning shears or secateurs.
• Prune off all dead, sick or dry wood.
• Shape the plant.
• Cut overgrown stems, which is part of shaping, but the idea is to keep the same size of the past year.
• Thin the peony, in case it is too dense, especially inside.
• You may need to shape, keep in size or thin, two of these or all three, but never remove more than 1/3 of the plant!
• Again, sterilize the blades with each plant.

With tree peonies, over fall and winter, you also want to remove all the leaves that fall to the ground, to avoid fungi and infections.

7: How to Prune Intersectional (Itoh) Peonies

For intersectional (Itoh) varieties of peonies, the pruning is even simpler, but you will do it in two stages.

• When frost and winter comes, just remove all the dead leaves. Then wait…
• In late winter (or early spring), cut all the dead or dry wood. You need to wait till the cold season is over to see which stems have survived and which not.

And this is all about pruning.

8: Divide and Propagate Peonies

First of all, there is no need to divide peonies. You can leave them in their spot and they will last you for decades. However, it is virtually impossible to propagate them by seed. So, if you want to get more plants from a clump (or you want to give some to a friend, fall is a good time, usually from late September to early November, or, in any case at least 2 weeks before the first frost day.

Now, peonies have very wide roots! They are not that deep, but they really spread horizontally, so you will need to check the dripline first. This is the line that drops from the outermost leaves to the soil. The roots of your Paeonia will have reached that point at least, if not even further.

Now, here is how to divide them…

• Water the peony the day before.
• With a fork, dig around the whole peony, keeping at least 4 to 6 inches (10 to 15 cm) from the dripline.
• Lift all the peony and its roots.
• Clean off the soil, you can use a hose, or do it by hand (I prefer it).
• You need to see the eyes, or shoots, and the roots well.
• With sharp and sterile blades, (shears and secateurs are better than a spade, but you can still use it), cut off a section of the plant that has at least 5 eyes (shoots) and lots of roots.
• Now you will need to replace the main clump in its hole and transplant the new part.
• Make sure you provide good soil to fill the holes and then water thoroughly.

Remember to use very well drained, fertile and organically rich soil for your peonies, and to find them a sunny spot where they can thrive and blossom when you transplant them.

9: In Very Cold Climates… Protect Tree and Intersectional Peonies

If you live in a very cold country, you may want to protect tree and intersectional peonies over winter. Mulch will do for their roots and for herbaceous varieties, but a breathable cloth like burlap, around the stems of the other types will keep them comfortable if you expect an extremely severe winter.

Winter Care for Healthy Peonies – And Lots of Flowers!

Cold hardy and generous, peonies are, however, fairly demanding plants when it comes to preparing them and looking after them in the cold season. Once you work out which type you have (herbaceous, tree or intersectional) and you adapt how you care for them to your climate, you can rest assured that next year they will grow back vigorously and ready to blossom!