Winter can be tough on plants, especially when temperatures drop suddenly overnight. Your lush garden can go from green and lively to limp and lifeless in no time.
But chilly air alone isn’t always the culprit. How plants respond to sudden cold, moisture, wind, and even their location in your yard can all impact how and when they freeze.
Let’s walk through some of these factors so you are better equipped to protect your plants when Old man Winter dodders into your area. As always, though, seek out a professional gardener if you need a little expert guidance.
Prolonged cold
Freezing temperatures can harm your plants, but what matters most is how quickly the temperature drops and how long the cold lasts.
Greg Grant, a horticulturist with Texas A&M AgriLife Extension, says, “Plants that don’t have time to adjust to the cold are more likely to have water in their cells freeze and rupture them.” That’s why a sudden freeze is more damaging than a gradual cooling.
Many native plants can handle brief dips below 32 degrees Fahrenheit without much damage, as they are used to short freezes. However, when temperatures fall rapidly or stay below freezing for several days, the cold starts to cause more damage.
Prolonged freezing can cause the water inside plant cells to freeze, rupturing tissues and blocking the flow of nutrients. It can also freeze the water around the roots.
Depending on how cold it is and the type of your plant, freeze damage can become evident almost immediately after a freeze or take a few months to appear. Usually, though, you can see signs of damage about a week after the freeze.
Here’s how each type of freeze affects plants:
- Light freeze (29 to 32 degrees Fahrenheit): Can be fatal to delicate plants
- Moderate freeze (25 to 28 degrees Fahrenheit): Kills leaves, buds, and young stems of many plants
- Severe or hard freeze (below 25 degrees Fahrenheit): Causes significant injury or even death to most plants
Read related: Signs of Freeze Damage on Plants
Water
Water keeps plants alive, but in freezing temperatures, it can quickly turn against them. When temperatures drop below freezing and stay there, the water inside plant cells turns into ice crystals and starts to puncture cell walls.
To protect themselves, plants try to move moisture out of their cells and into spaces between them so ice doesn’t form inside. But the issue is that this causes the cells to lose water, leading to dehydration and cold damage.
Water around the roots also freezes, which makes it difficult for plants to absorb moisture from the soil. When there isn’t enough water, plants struggle to move nutrients throughout their system.
Wind
Cold wind when it’s freezing makes the situation worse for plants. “It accelerates heat loss around the plant and moisture loss from the plant and soil,” says Grant.
This rapid moisture loss, called desiccation, dries out leaves and stems. When plants lose too much water, their tissues dry out and become more vulnerable to freezing damage.
Even if the temperature is around 40 degrees Fahrenheit, strong cold winds can still cause plants to freeze as moisture evaporates from their surfaces.
Plants in open areas suffer the most from cold winds. Those near walls or fences get some protection and retain moisture longer.
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Location of plants
Even within your yard, temperatures can vary a few degrees from one spot to another. Cold air is heavier than warm air, so it naturally sinks into low-lying areas of your yard and forms frost pockets. Even bushes and hedges can act as barriers that trap cold air. That’s why plants in these areas freeze first, while those just a few feet away don’t.
Plants on flat surfaces near patios or fences take longer to freeze, as these structures absorb and radiate heat.
Plant type and age
Plants don’t all freeze the same. Herbaceous plants are more prone to water damage, as they contain more water in their leaves. Even if they can naturally move moisture away from plant cells in freezing temperatures, ice can form and rupture the cell walls if there’s just too much water.
Woody plants resist cold better because their bark protects inner tissues from freezing. However, when the ground itself freezes, even these plants dehydrate as they can’t draw water from the ground.
Tropical or subtropical woody plants aren’t as hardy and can suffer more severe damage from the cold.
Younger plants usually die during a freeze because their cells contain a lot of water and their tissues are still tender. They also don’t have a strong root system that can draw water from the ground to rehydrate them.
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Soil moisture
“Moist soil retains heat better than dry soil and helps protect your plants from the cold,” says Grant. If you didn’t water your soil before a freeze, it cools down fast and doesn’t insulate roots as well.
You also need to consider that the sandier your soil is, the more likely it’ll lose moisture during cold weather, so the plants won’t be able to store heat for long.
FAQs
Native plants are better adapted to the conditions of your area, but they can still freeze if the temperature drops suddenly or stays below freezing for days.
Plants that are in low-lying areas usually freeze faster as cold gets trapped there.
Cold winds can make the plant lose moisture faster and lower the surface temperature to below freezing when the actual temperature is higher.
Protect your plants from freeze damage
If you know what causes your plants to freeze, it becomes easier to protect them from the cold. But protecting your garden during winter takes time and hard work. If you’d rather leave it to the experts, get in touch with us.
Lawn Love pros can handle your gardening needs, mow your lawn, and aerate it. Hire a pro through Lawn Love today to get the job done right at a price you’ll love.
Main Image: Plants covered by frost. Image Credit: Stanislav / Adobe Stock
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