Whether you never got around to planting or aren’t quite sure where to place your perennials, rest assured that many other gardeners still have plants in containers. Even if they are hardy in your zone, perennials in containers are subject to much harsher winter conditions than those in the ground. Frigid air temperatures and drying winds can be particularly damaging to the root systems of plants in containers. Soil heaving often occurs, which can break-up the roots and leave plants vulnerable to severe conditions. Fortunately, there are a few effective methods that can be used to get containerized plants through the winter.
Store Your Perennials Indoors
An unheated garage, shed, or basement with a temperature range between 30 and 40 degrees can provide a perfect environment for overwintering perennials. Dormant plants should be brought inside and watered periodically whenever the temperature is above 40 degrees.
Dig Containers Into The Soil
If you don’t have an appropriate indoor space, perennials in containers can be dug into the soil. Sink perennials until they are sitting at the same level as the surrounding ground. This will help moderate the soil temperature in the containers, avoiding excessive freezing and thawing.
Group and Protect Your Containers Outside
If digging into the ground is not an option, containers should be grouped and placed in a protected area out of strong winds and intense sunlight. Surround the containers with straw, leaves, or bark mulch. Watering should continue until the soil freezes and as long as the temperature is above 40 degrees. If all goes well, your perennials should be ready to plant in the spring.
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