Overwintering Container Planters
Trees, shrubs and perennials are great for container gardens. But as winter approaches we need to provide a bit of care to help them through the winter.
The roots of plants growing in containers overwintered will be exposed to extremely cold temperatures that can damage or kill the roots and even the plant. Grow plants that are at least one zone hardier than your zone if you plan to leave them out for the winter. Make sure your containers will tolerate the challenging winter weather as well.
I have several large plants in containers that I overwinter above ground. I shove them against my garage in a sheltered location. I surround the pots with straw, bags of topsoil, annual pots and similar items for added insulation. Then I cover with snow throughout the winter.
Or, try moving them in an unheated garage. Insulate the roots with packing peanuts or other items you may have in the garage. Water whenever the soil is thawed and dry.
A bit more information: Next year try growing perennials, trees and shrubs in functional nursery pots that rest inside a beautiful container. In fall lift the potted plants out of the decorative container and bury the pot in a vacant area in the landscape. Cover the pot with soil and let nature take care of the rest. Or, move these plants into the landscape in fall for added long term beauty. Next spring buy new plants for your pots. You can have beautiful containers and expand your planting beds.