My containers of ivy sometimes don't make it through the winter.they must stay outdoors. Will watering in the dead of winter help?
How Can I Make Plantings of Ivy Survive Winter?
Certified GKH Gardening Expert
When plants are in containers outside, they experience conditions that are 1 zone lower than yours due to the fact that they have no insulation around them. On top of this, when minor temp changes occur, they have nothing to help them maintain a constant temperature and they can start to come out of dormancy prematurely, which means they have no internal protection against the cold. The thing that most commonly kills container plants outdoors is temperature fluctuations.
In order to try to stop this, the best thing you can do is try to replace the insulation and constant temperatures they would normally get in the ground with something else. Placing the ivy containers near a foundation will help. Wrapping the pots in an insulator of some kind, like wire wrapped straw, bubble wrap or even housing insulation can also help. Mounding straw or leaves around the containers will also help.
Anything you can do to keep the container at a stable temperature will help keep them alive.