How would you like to sit outside all winter, feet buried in the cold soil, waiting for spring? Thankfully, most of us don’t have to. Your plants, on the other hand, have no other option (unless you dig them up and invite them inside for the holidays). The good news is that many of the varieties of shrubs, trees, and flowers we have in our backyards have been planted because they survive in our specific climates and are, by nature, well-equipped to face a substantial portion of winter’s perils.
However, plants aren’t eskimos, and they’re still vulnerable. Because winter weather is unpredictable, strong wind, snow, and ice may still wreak havoc on plants that are under-nourished, less hearty, or planted in a location that provides little protection from the elements.
So what can a savvy gardener do? With the appropriate care and preparation, many of your plants will sail right through the stormy winter months!
Read on for factors that affect plant survival and some hot tips that’ll save your plants from freezing!
Factors that affect plant survival during wintertime
How plants fare in winter weather is significantly affected by an important factor: the temperature outside. Colder temperatures stop plant growth and prevent water from circulating through a plant’s sap, which delivers important nutrients and sugars throughout the vascular system. One way to prevent losing plants come wintertime, then, is to plant smartly based on a plant’s predicted survival rate.
The U.S. Department of Agriculture has provided a helpful map highlighting “cold hardiness zones” within the country based on geographic location that tells the lowest minimum average temperatures for specific regions. When buying plants, the zone that corresponds with the regions at which a plant is expected to flourish will be indicated on the tag. In Minnesota, nurseries are legally required to indicate if a plant cannot survive the winter or reliably produce fruit. Tomato plants, for example, won’t survive the winter. The tropical hibiscus plant could not last a Minnesota winter.
However, cold extremes are not the only reason plants die. Even plants that are expected to make it require some protection during the winter season. Here are several other factors that affect your plants’ continued growth:
- Less sunlight: Plants need sunlight for photosynthesis, the process by which they create food.
- Temperature fluctuation: Ideally, the ground would slowly cool during winter, then slowly warm up during the spring. Unfortunately, it’s more common to have quick bursts of freezing, and then warming spells from winter sunlight or milder days (this is called “heaving”). Changing conditions can harm plant growth.
- Snowdrifts and ice storms. The physical presence of snow and ice can cause plant breakage.
The reason plants can survive winter
Despite all the factors fighting against their survival, your plants can make it to spring! Here’s how it works for different types of plants. Woody plants have extra protection against the cold, and they send sap down to their roots to keep it well-nourished. For perennials, snow acts as a nice protective blanket, keeping in warmth and protecting the ground from sporadic temperature changes. Although annuals die every year, their seeds are protected deep in the soil. Plants that store up nutrients underground, like onions, tubers (like potatoes), and tap roots (like carrots) stay alive for just that reason.
What can you do?
You can’t make the weather warm up, but you can create ideal survival conditions for your plants. Here’s how:
Take extra care of your plants during spring and summer. Healthy plants will always survive better than sick ones. Plant stress happens for many reasons – whether dryness or over-saturation, insect infestation, disease, or lack of nutrients. Prevent this by watering and fertilizing plants regularly.
Mulch. This extra layer of protection will insulate your plants, especially if snow doesn’t come immediately. If you create a protective cover about 6-8 inches thick with wood chips or straw mulch, the roots will be more likely to survive the cold of winter.
Cut back deadheads and foliage on perennials. If you leave it, it could cause the plant to retain too much water come spring and begin to rot. Removing dead or dying parts of the plant gets rid of vulnerable spots and ensures the plant will be healthy after winter’s end.
Reduce water loss as much as possible. Plants transpire (lose water) during sunny winter days and windy days, too, and you don’t want them to wither up and die for lack of liquid. If you have a period where there’s not been much snow or rain, and a freeze is expected, it could do your plants good to water then. Evergreens, especially, will benefit from extra watering.
Cover foundational shrubs. Falling snowdrifts or icicles from the roof can damage plants near your foundation. To prevent breakage, cover shrubs near your house in burlap or other protective material, like protective commercial tree wrap or another material of a light color.