What Happens to Your Plants in a Warm Winter?

We have seen some unseasonably warm weather this winter so far, even with some record breaking temperatures.You may be seeing some growth in your garden as a result, maybe even a few blooms, but there is no need to panic just yet. Typically plants suited to this climate zone can handle a bit of wacky weather. They require a long period of cold, freezing weather before they will start to grow or bloom. Some cultivars and species that are more accustomed to the south, require a shorter cold period, and a winter warm up after a brief period of cold weather, may trick them into thinking spring has arrived. 

How things go will depend on when we get cold weather, how cold it gets and how quickly. If things go from balmy to frigid in a very short period, it will cause more stress and damage to plants, but it is unlikely to kill them. If we experience a winter with a sudden cold snap, followed by a second period of warm weather, expect even more damage. If we get gradual cooling and consistent freeze, we can expect less damage.

Here is a breakdown of what kind of damage you might see:

Annuals - Some cold hardy annuals like snap dragons may be giving you a longer bloom time. Since freezing winter temperatures kill annuals anyway, there is no need to worry, just enjoy the bonus blooms.

Perennials - Most of their important parts are stored below ground and are dormant, so very little damage should occur. If you have good soil and a thick layer of mulch over your garden, most perennials will be fine.

Bulbs - Daffodils and hyacinth may have started to grow leaves in this balmy weather, but fear not, the flower parts are still safe underground and will be fine for next spring. The leaves that have grown will likely see some damage once the cold sets in.

Lawns - Grass got some extra time to get roots established for the winter, so this weather may actually help your lawn. Where you will see damage next spring is in low lying areas where puddles of water freezes into ice, which can kill the grass underneath. White grub populations were kicked back in the past two years with the cold weather, but a warmer winter may mean that more grubs survive the winter, and cause more damage next spring and summer. 

Deciduous Trees and Flowering Shrubs - Native trees such as Sugar Maple and White Birch are tough and can handle wacky Canadian weather. A few buds and/or branches may get damaged, especially with a sudden freeze, resulting in less flowers and seeds next spring, but the tree itself will be fine.

Coniferous Trees (Evergreens) - These have taken a beating the past two winters with wind and salt burn, drying them out, or even killing them. The warmer weather this year means less salt spray and less cold, drying winds. The unfrozen ground and December rain means they have access to more moisture, so there is less chance of them drying out in the warm weather. If we do get a sudden, fast cold spell, you may seem some damage to tender branches. Make sure they are in good soil and mulched well. If they are exposed to high winds or salt spray, consider protecting them with burlap.

Fruit Trees - Stone Fruit trees like cherries and plums may be more affected by warm weather and a sudden cold snap than apple trees. You can expect less buds, blooms and fruit next spring. If you do an early spring pruning, take extra care and try to cut off as few new buds as possible to increase yields.

Tips for Keeping your Garden Safe from Wacky Weather:

  1. Put the right plant in the right place - Know your hardiness zone, sunlight and soil conditions and match plants that are best suited. 
  2. Keep your soil healthy - Good soil is the best thing you can do for your garden. Use soil with good drainage and organic matter.
  3. Mulch, mulch, mulch! - Mulch acts a protective blanket for your soil, which is home to plant roots and the plant energy over the winter. 2-3 inches of natural mulch protects plants from extreme cold and heat.
  4. Drainage - Too much or too little can further stress your plants in wacky weather. If you cannot change or improve the drainage of an area, make sure to use plants that are best suited to those conditions to minimize stress.