If you are growing peonies in a cold climate, you may wonder how these plants handle cold temperatures. One aspect to consider is whether or not peony roots can freeze. We’ll dive into this question and cover how to protect your peonies during cold weather best.
Can Peony Roots Freeze?
Yes, peony roots can freeze. And this is a natural part of their life cycle!
Since most types of peonies are hardy to areas as cold as zone three, they are well accustomed to cold weather. Therefore, you don’t necessarily need to be concerned about peony roots freezing.
However, the roots can become damaged if they undergo multiple freeze/thaw cycles. Just think about what veggies look like when they freeze and thaw!
Freeze/thaw cycles can also lead to an effect known as heaving. This occurs when moisture below the soil surface freezes, pushing rocks, roots, and other materials upwards.
When the temperatures warm, the water melts, and objects settle. When temperatures cool, the water refreezes and heaves objects even further up.
Over time, peony roots may become exposed to the air and wind, damaging them.
Fortunately, preventative practices can easily prevent this from occurring.
Protecting Peony Roots
While you may think that covering peony roots with more soil will insulate them from temperature swings, don’t do this!
Peony roots like to be planted under just a few inches of soil. If you plant the eyes of peony roots more than two inches under the soil, the plants are unlikely to flower.
But don’t worry—there’s another way to protect your peony plants!
Mulching your plants with straw, leaves, or wood chips in the fall will help protect the roots over the winter. That’s because this mulch will insulate the soil, protecting the roots.
When temperatures begin to remain above freezing, you can remove the mulch and allow the plants to grow.
Should I Dig Up My Peony Roots in the Fall?
If you’re still worried about your peony roots freezing, you can dig them up in the fall and move them somewhere warmer. However, this option is often unnecessary.
Remember that peonies require a certain number of chilling hours to thrive and produce flowers. If you dig them up and bring them inside where it’s warm, the plants are unlikely to produce the flowers they’re known for.
However, you can dig them up and place them somewhere that is cool but not cold (32ºF-40ºF) during the winter. This will allow them to receive the chilling hours they need to bloom but prevent them from freezing.
If you opt to use this method, replant the peonies in the spring once the ground has thawed. But don’t worry about light frost—the plants can handle this!
What Zones Can Peonies Grow In?
Peonies can grow well in USDA hardiness zones 3–9. The peony variety can impact the exact zones in which the plants will thrive.
The zone you live in will impact how you should care for your peony plants over the winter.
If you live in a zone where the temperature remains below freezing for most of the winter (zones 7–9), your plant’s roots may freeze briefly. However, the roots are unlikely to remain frozen.
Therefore, you should mulch the base of your plants to protect them from fluctuating temperatures. Layering a few inches of straw, hay, or wood chips on the soil’s surface will help protect the roots from cold temperatures and temperature swings.
If you live in an area where air temperatures are often below freezing, mulching can help protect the plants from the cold.
What If My Peony Roots Become Exposed?
While peony roots should only be buried under a few inches of soil, they should not be exposed to the air. If winter heaving or erosion leads the roots to become exposed, you should take action ASAP.
Cover the roots with a few inches of soil and lightly pack the soil in place. If it’s winter, you can then mulch the area to insulate the roots and also protect the soil from erosion.
However, during warmer temperatures, you can simply cover them with some soil and let them continue growing.
Provide Your Peonies with the Proper Care
No matter where you live, you must provide your peonies with the proper care. Protecting them from fluctuating temperatures will help them thrive and produce lots of beautiful blooms.
For more, see our ultimate guide to growing peonies in your garden.