Ready for Ice?

As we move into February we also move into one of the most precarious months for the garden and landscape. But how can this be when everything is dormant and we’re weeks if not months away from planting, blooming and harvesting? A few key words: climate change, cold, ice and salt.

Historically, February is our coldest and snowiest month. This always surprises me because the gardener in me tells me that it should be December or January. But the statistics don’t lie, and February is the month when we see the coldest temperatures as well as the most amount of snowfall. But as the earth warms we’ll be more and more likely to have ice storms out here than snowstorms. This will result in broken branches, broken limbs, fallen trees, crushed shrubs. And how will you melt this ice on your walkways and driveways? In most cases it will be salt — pure crystal sodium chloride. Yup, the same stuff that your doctor warns you about can do irreparable damage to your plants. And yes, in some cases, your salty ice melters can and will kill your plants.

Let’s take a step back and think about ice and ice storms. Ice and wet snow buildups on our outdoor plants can be a real issue. More than a 10th of an inch of ice accumulation is the point at which we begin to see potential damage. And if it’s not ice, but heavy wet snow, similar damage can occur. The first plants to suffer are plants like the hydrangeas that retain their faded flowers in round or pinnacled shapes atop thin stems that grew last summer. As the ice or heavy snow accumulated on these faded flowers the weight causes the stems to arch, sag then break.

This damage leaves the plants ragged and sometimes crushed to the point where a complete spring rejuvenation is necessary, and flowering can be delayed for a year. There is a simple solution, though. Simply prune the flower heads and let them fall to the ground or compost them. You’ve reduced the weight on the stem and eliminated most of the danger from ice and wet snow accumulation. Know what variety of hydrangea you’re dealing with though so you know how much pruning you can get away with. You can always trim off the spent flowers but how far the stems can be cut will depend on the variety and the effect you want for next summer.

There’s also the snow and ice that falls from your roof down onto your foundation plantings. This ice and snow can crush azaleas, rhododendrons, Ilex and boxwoods and just about any other shrub or small tree where the snow or ice tends to drop. Again, proper pruning can help, but proper planting would have even been a better idea. Landscapers and landscape architects rarely consider the hazards of ice and snow falling off a roof — so you need to. There are several ways to protect these plants. For a small landscape or house, you can usually handle this work, but for larger homes with more ambitious plantings a landscaper or experienced gardener can install the burlap, tie the plants or make an appropriate cage.

It’s also important to make sure your gutters are clean and the downspouts are not clogged with leaves and twigs. When gutters back up this exacerbates the problems of falling ice, tumbling snow and even crashing gutters.

Then on to the driveway and walkways. Most of us don’t think twice about grabbing a small bag or container of ice melter and sprinkling it liberally to manage the slip, fall and skid dangers. One word of advice: Don’t!

Pure salt, or sodium chloride, even in small quantities, kills plants and can make areas unplantable for months. This type of salt kills virtually all parts of the plants, but especially the roots. When applied by spreaders behind trucks you can see the damage just days later to pine needles and to other evergreens near the roads and highways.

Salt (also known as rock salt) does have its place though as it will melt ice better than most other melters at very low temperatures down to 10 degrees. This is why it’s used on our highways and byways, but any highway manager can tell you how much damage salt can do to not just the road bed but the steel that reinforces that road bed and the infrastructure that’s beneath and along the highways. It can also contaminate our freshwater supplies in critical recharge areas.

Just for reference purposes, the New York State Thruway Authority applies 40 to 80 tons of rock salt per road mile per year. That translates to 15 to 30 pounds per linear foot per year. We don’t use that much out here, but think about that tonnage and poundage and the potential environmental and physical (as in your car) damage this much salt can do.

You do have other choices though, and some are much, much safer. The first is calcium chloride. It’s about 10 times more expensive than rock salt and works below 10 degrees F. It is not nearly as damaging to plants as sodium chloride, but don’t get complacent — it can still damage plants and their roots but just to a lesser degree. Calcium chloride also leaves a white residue that can be tracked indoors.

Magnesium chloride is also an excellent ice melter and works well down to -5 degrees. It was very hard to find last winter but seems to be back in limited supply. While it’s very, very expensive it’s the chloride ice melter of choice when it comes to limiting plant damage. It’s also the choice when used on steps and entryways when pets are involved as it’s least likely to affect dog and cat paws.

There are even safer alternatives. Urea is also an ice melter but it’s only good down to 13 degrees F. It’s pet safe, but there are some comments that the pellets are better for giving traction than for ice melting. Urea is often found in lawn fertilizers — if you’re in a pinch.

Ashes from the fireplace are good for traction but the only melting comes from the fact that ashes are dark in color and may absorb some heat. The downside is that ashes are the last thing you want to track into the house. I always keep a bucket around though, just in case.

One other fertilizer that can also act as an ice melter and traction booster is Milorganite. This material is organic and thus very safe to use but has a limited melting capacity. It only melts ice in sunlight and at higher temperatures. Since it’s black it also absorbs heat and also aids in giving traction. Other pluses are that it’s a fertilizer, won’t hurt pooch’s feet and offers some deer repellency.

Lastly, and by no means least, there is sand, but just not any sand. Playground sand has tiny particles and can be nearly useless so the sand of choice is either builders sand or traction sand that has the most grit. None of these are ice melters but are great when only traction is needed. Light ice accumulations often need only a light coating of coarse sand to do the trick. If you want to add some melting power and be left with some residual traction you can mix coarse sand with a salt material. I keep a 5-gallon (covered) pail of sand mixed with a small amount of calcium chloride to treat my steps at the front and back doors.

There are some brine or liquid salt solutions available as sprays to preapply to walkways and steps similar to the brand the state uses to pretreat roads that tend to ice up first. Never use these at home. Any drift of the spray will kill any plant material it comes into contact with and the liquid forms of these salts will kill roots faster than the other forms of ice melters, especially after repeated use.

Storing any salt-type (chloride) ice melter from year to year can be a challenge as it tends to absorb moisture from the air and solidify. Have enough for emergencies, but don’t end up with bags and jugs of solid and useless ice melters. Be gentle to your plants and hardscape. Keep the use of salt-based ice melters to a minimum and use traction materials as possible additives or replacements. Keep safe, protect your plants. Keep growing.

Speaking of the weather, the long-range forecasts for February and March are hinting that February may be the better month to get out and do your fruit tree pruning and any other winter garden work. February is looking to be warmer than normal with average to below-average precipitation. One forecaster is saying that our coastal area has little to no chance of major snows in February. But things change in March with colder than normal temperatures and precipitation. If we do get a winter wallop, then March looks to be the month. There may even be a polar vortex event that would make March very, very cold. We shall see but hopefully this will help with your planning as well as your planting.