Why did I lose so many perennials last winter when the weather was so mild?
The mild weather was likely a big part of the problem. We have a tendency to think of hard winters as those that are extremely cold and/or snowy because those are the conditions which cause us the most distress.
Plants, however, view the world a little differently than we do.
Extreme cold can certainly kill any plant that is only half-hardy in our area. It often happens that we drag something home from a garden centre that isn't really meant to grow in this area but we luck out for a few years and forget that we've been pushing the boundaries until a particularly nasty deep freeze sets in and our luck runs out.
Most of us are familiar with that scenario.
What catches us off-guard is when our hardy perennials die after we've gone through what seemed like a mild winter. This happens because the combination of mild temperatures and minimal snow cover can be much harder on plants than a deep freeze. Plants are designed to go dormant when the temperatures drop and to stay in that slowed down state until things warm up again in the spring. When you get a mild winter like the one we just had, the constant fluctuations in air temperatures that are relatively mild cause plants to get confused over whether or not they should be dormant and this confusion can prove fatal.
Those gardeners who actually put the time and effort into mulching their gardens faired better this past winter than those who didn't because that mulch would've insulated the ground, preventing soil temperatures from fluctuating in tandem with the air temperature thereby protecting plant roots from constantly going back and forth between freezing and thawing, which would have improved their chances of survival.
Snow is an excellent insulator. If we'd actually had any this past winter, it would've had the same effect as mulch. Since we didn't, perennials you wouldn't normally have expected to be winter-killed were. Although it can seem as though there is no rhyme or reason why one plant will die while the one next to it survives, generally speaking, the healthier a plant was going into winter, the better the chances were it would make it through to the spring.
If you have any questions or comments, please send them to me at vanessa@gardenmuse.ca.
