Shoveling in single-digit temperatures after the colossal winter storm this weekend, I dumped mounds of snow onto my garden beds, knowing it would protect my trees, shrubs and dormant perennials.
When the ground repeatedly freezes and thaws, as it does over winter in cold climates, that can squeeze roots, seeds, bulbs, tubers and rhizomes right out of the earth. Once exposed, they can be killed off by cold, drying winds.
But snow cover provides a heavy blanket of winter mulch that insulates the soil, prevents heat from escaping and keeps soil temperatures from seesawing. And as it melts, snow will not only water your garden but fertilize it with plant-boosting nitrogen absorbed from the air on its way to earth.
It’s a perfect display of nature taking care of itself.
Branches might not fare as well
On the downside, the same heavy blanket that keeps plants warmly tucked in can spell disaster for evergreen trees like arborvitae and Leyland cypress. When wet snow accumulates on trees, its weight can bend, buckle or snap branches. And if you don’t remove it, it can permanently disfigure them.
We can help by gently knocking snow off branches with a long-handled broom. Under normal circumstances, I do this after the storm ends. But during extended snowfalls, I go out during the storm, as well, to keep on top of the accumulation. Trees are expensive, so I’d rather brave the elements than have to replace them.
When water or accumulated snow freezes into ice, however, it’s best to leave the branches be. Attempts to crack or knock ice off plants risk further damaging bark and other delicate plant parts. All we can do is allow it to melt naturally and hope for the best.
Use garden-friendly salt
After removing snow from walkways and driveways, it’s good practice to apply rock salt to prevent ice from forming. But choosing a product can be confusing.
Magnesium chloride is the best choice, as it dissolves quickly to coat and melt ice, works in temperatures as cold as 10 degrees below zero Fahrenheit and is less likely to burn pets’ paws. It’s also the safest for your plants, which become exposed to the product via wind, soil runoff, melting snow and splashing slush, as well as deliberate snow dumping.
One drawback, however, is that magnesium chloride is also the most expensive of the commonly available ice-melt products. If your coverage area is so large that using it exclusively becomes too expensive, consider using it in areas adjacent to plants and where pets will be exposed. Then, opt for my second choice, calcium chloride, in less-trafficked areas and those away from lawns and gardens.
You’ll often see calcium chloride marketed as pet- and plant-safe, but it still can damage plants and irritate pets’ (and your own) paws. Wear gloves when handling it. If you must use it near plants, apply sparingly. And rinse pets’ paws after exposure.
As a gardener, you might recognize the chemical name of another type of rock salt, potassium chloride. Although it’s also a component of balanced fertilizers (the K in N-P-K ratios), the amounts needed to melt ice can actually harm or kill plants, so avoid using it as a deicer.
Sodium chloride is the cheapest of the bunch, but the worst choice for plants, pets and the environment. It can corrode cars, crack concrete, and poison wildlife, plants and trees.
When applying any ice-melt product, always use the least amount necessary, as they all have some potential to damage masonry. Applying a waterproofing sealant to driveways and walkways during warmer weather will help protect against ice-related cracks for several years.
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Jessica Damiano writes weekly gardening columns for the AP and publishes the award-winning Weekly Dirt Newsletter. You can sign up here for weekly gardening tips and advice.
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