Perennials in containers are definitely harder to keep alive through winter than their counterparts in the ground. The ground insulates and protects them more than a container does. If you would ike to keep your potted perennials for next year we’ve got tips that should help you.
Choose the right pot
The bigger the pot, the more likely you will be successful overwintering. This is because there is a larger volume of soil in a bigger container to help insulate the roots, which protects them from freezing and desiccating. Be sure the container material can withstand freezing temperatures.
Water them before the ground freezes, but not after
Containerized perennials should be watered just before the ground freezes to give the plant a reserve supply to use during warm winter spells. If possible, overwinter them under cover so they don’t get much water from rain because they will not need it during cold temperatures and you don’t want the roots sitting in cold water.
Move them to a protected area
You can overwinter them by moving the pots into a cold frame, shed, or unheated garage for the winter after the first hard frost. You don’t want to bring them inside or anywhere too warm because they require a period of dormancy to bloom. They don’t need light during this time, but keep an eye on the soil. If they dry out too much they will die. Ideally you’d keep the soil slightly damp, not too wet.
Group them together on the ground
If you have to overwinter your containers outside, place a grouping of pots as close together as possible on the ground so they can huddle together and absorb the heat from the ground. Don’t bring them onto a raised deck or balcony because they’ll be too cold and exposed.
Insulate the container
You should cover the pots with some sort of insulating mulch like leaves or straw.
Try wrapping the pots themselves in insulating material for extra protection.
Move your perennial containers to safety before the first frost. The average first frost in eastern Sussex County is the end of October. Keep an eye on nighttime temperatures. Get your pots hunkered down for the winter and, like most of us, they’ll be happy once spring arrives again.