Overwintering shrubs and perennials in pots


Hi There,
I hope this email finds you well. Can shrubs like boxwoods and perennials planted in pots survive Toronto winters?


Thank you contacting Toronto Master Gardeners. For container planting it is recommended to select plants that are hardy two zones colder than your hardiness zone. Since Toronto is zone 6 and boxwoods are hardy from zones 5 to 9, your boxwood might not survive the winter. This rule applies to the perennials as well.  Careful preparation will increase the likelihood that plants in containers will survive the winter. You need to:

  1. Choose pots that will withstand the cold such as metal, heavy plastic, wood, fibreglass, ceramics fired at high temperatures.
  2. Keep plants well watered up to the first frost.
  3. Insulate the pots.
  4. Move the pots to a sheltered position away from winter winds.

Good luck with your plants.

September 30, 2021