Plants growing in containers should be sheltered, put in garage or sunk into soil over winter. They also need water.
Alma Gaul
As you prepare your landscape for winter don’t overlook the trees, shrubs and perennials you have growing in containers. These need a bit of extra protection to help them survive cold winter temperatures.
The small amount of soil in container gardens does not always provide sufficient insulation. The roots are more exposed to temperature extremes than those of their counterparts growing in the ground. Extremely cold temperatures can damage or kill the roots and even the plant.
Plants rated at least one zone hardier than your zone can usually survive when left outside for winter. Just make sure your containers will also tolerate the challenging winter weather.
Here are a couple strategies for helping your other containers through the winter. Select the one that best fits your landscape space and gardening style. Those in apartments or with limited space may need to enlist the help of their gardening friends.
Sheltered location. Move containers to a sheltered location. Place them close together for added insulation. Then surround this with annual pots of flowers and vegetables to further insulate the roots. Wait until spring to empty and compost the annual plants. Or cover the pots with woodchips or surround them with bags of leaves, potting mix or bales of straw. Add another layer of insulation by piling snow that is free of deicing salt over the pots throughout the winter.
