Fighting the icy elements

In light of the fact that we’ve already set a historical record for snowfall, and with predictions that this will also be one of the coldest winters in the last 20 years, it’s pretty obvious that there’s going to be a lot of ice around in the next few months.

This icy situation causes obvious problems for anyone and anything that need to get around. But in our efforts to tame the slips and slides, we apply a range of chemicals that can have disastrous effects on our landscape and hardscape.

With this in mind, I thought it might be a good idea to again review the various ice melters, their drawbacks (yes, some have benefits), and a few thoughts for getting some safe travels around the property.

Gaining Traction

First, let’s talk gripping action. Here we’re concerned with safety underfoot and not so much with melting. The solution here is simple and it has no effect on our plants. It’s sand. Available in bags, there are actually several types of sand and a few that work better than others.

The best sand to use for traction is coarse sand sometimes sold as “traction” sand. The sand particles are angular in shape so they tend to lock onto instead of roll off the surface. Playground or sandbox sand, as well as our beach sand, has much smaller rounder particles and offers much less in terms of traction and stability. Builder’s sand falls somewhere in the middle and is acceptable if the coarser traction sand isn’t available. Coarse stone dust is also a good substitute.

For getting some good traction, cinders and ash from coal burning boilers were used when I was a kid, but I never see them used any more. Ashes from the wood stove or fireplace can be used, but unlike sand, ashes will stick to your boots and shoes and end up in the house. But it’s always a good idea to keep a bucket of ashes around just in case as they can do wonders when you can’t seem to get the car out of the parking space or driveway.

Kitty litter and bird seed are also good standbys that you can keep in the garage or in the trunk of your car for when such an emergency presents itself.

Ice Melters

Next we move on to the melters. We use lots of chemical ice melters

that kill our plants. But there are ways to beat the ice without beating up your plants while at the same time causing less damage to your flagstone, blacktop and concrete.

If your concrete patio or sidewalk is new, the professionals suggest that you refrain from using any chemical de-icers as their use may result in scaling (surface separation) of the concrete. Instead, clean off as much loose snow as possible before it turns to ice and use sand or any of the gritty materials noted above instead of melters.

In other circumstances, there are a number of de-icers that you can take advantage of, starting with good old salt (sodium chloride). Sold as table salt, rock salt or ice cream salt, it is the most used and least expensive de-icer. Remember though that this material works only when the surface temperature is above 10 degrees Fahrenheit. And it will definitely damage and can kill adjacent turf, shrubs, trees and possibly bulbs and dormant perennials.

Be careful when applying salt also, since blowing salt dust can do damage to evergreen plantings many feet from where you put the material down. You see this quite often when road sanders put salt down near pine trees and the pines “mysteriously” die the following spring. The most obvious first symptom of salt damage is that the trees quickly brown on one side only—the road side. However, the most severe damage doesn’t show up until the growing season.

Remember also that salt is corrosive to metal. So after applying it, clean your tools and spreaders carefully.

Salt should be applied at the rate of about 1 to 3 pounds per 100 feet. And don’t forget that when salt brine dries, it turns to a white powder which may be tracked indoors where it may do more damage.

Calcium chloride melts snow and ice faster than salt and remains effective to nearly 60 degrees below 0 degrees Fahrenheit. However, it is nearly twice as expensive as salt. On the up side, it has substantially less effect on plants, lawns or shrubs. But keep in mind that it is corrosive to metals. Apply at a rate of about 1½ to 3 pounds per 100 feet.

Calcium magnesium acetate melts snow and ice just as effectively as the chlorides, does not corrode surfaces and is less toxic to aquatic organisms, so it is the melter of choice if you live near a stream, pond or other body of water. It is, however, much more expensive than salt or calcium chloride, but this may be offset by the reduced costs of damage to infrastructure, tools and equipment.

In many areas, liquid forms of calcium magnesium acetate are used to pre-treat surfaces just prior to expected snow or ice and is referred to as an anti-icing treatment. This use often means sanding isn’t necessary since the precipitation rarely refreezes.

There has been a great deal of advertising for various liquid ice melters that can be applied prior to snowfall. These work great when used by highway departments, but they’re not terribly effective when used at home and the spray drift can kill plants very effectively. If you need a visualization of the various properties of ice melters, there is a comparison chart at the website icemelters.com.

Some fertilizers can also be used as ice and snow melters. The potassium component of fertilizers (potassium chloride) is what melts the ice, but remember that this too is a salt and overuse can cause burning to plant roots.
Nitrogen, in the form of urea, also has melting action. It does a good job although it’s expensive and is effective only above 11 degrees Fahrenheit, optimally when the temperature is between 25 and 30 degrees. When appropriate, it is the melter of choice in areas adjacent to landscapes as it does not harm, and may be beneficial, to plants. It is applied at the rate of 5 to 10 pounds per 100 square feet.

Another alternative is Milorganite, an organic nitrogen fertilizer. This natural product is black in color and thus absorbs heat from the sun when used during daylight. For this reason, and because of its chemical composition, it has some ice-melting ability but it can also double as an abrasive and it’s the only one of the group that’s also a deer repellent. Also remember that come spring, any place where it’s been used will get a special green-up instead of a die-back due to its nitrogen component.

It’s important to remember that fertilizers are more expensive than salt or calcium chloride and require greater quantities for the same results. Those containing ammonium nitrate are chemically corrosive to concrete and should not be used. Also, fertilizers are effective only when the surface temperature is above 20 degrees.

Post-Season Damages

We do know that certain plants are absolutely intolerant of salt damage from de-icing. The list includes: American elm; linden; apple; beech; box elder; boxwood; flowering quince; ginkgo; ironwood; hickory; hornbeam; mimosa; red, silver and sugar maples; sycamore; Douglas and balsam firs; hemlock; dogwood; rhododendrons (including azaleas); spirea; white and red pines; yews; roses; and bluegrass and fescue lawns.

Initial salt damage is caused by the burning effect on the foliage of evergreens. But later on, salt causes plant injury if it accumulates to excessive amounts in soil near the root system. This frequently happens when salt-laden snow is plowed off streets, sidewalks and walkways and onto the adjacent landscape.

Injury can also occur from salt dust that may be created as salting trucks speed by. This type of damage is most often noticed on roadside pines and junipers.

Anyone who has tried to get wet table salt out of a shaker (like due to the humidity out here in August) knows that salt readily absorbs water. Rock salt exhibits the same property in the soil and it absorbs much of the water that would normally be available to roots. Thus, even though soil moisture is plentiful, high amounts of salt can result in a drought-like environment for plants.

In addition, when salt dissolves in water, sodium and chloride ions separate and the chloride ions are readily absorbed by the roots. These ions are carried through the sap stream to actively growing portions of the plant, such as leaf margins and shoot tips, where they accumulate to toxic levels. What we then see are the characteristically scorched or “burned” margins.

The symptoms of salt damage that you may notice only later in the spring, or much later, may appear similar to those problems associated with drought or root injury. Stunted, yellow foliage, premature autumn leaf coloration, death of leaf margins (scorch) and twig die-back are common.

When conifers are injured by winter deposits of salt spray, the affected foliage turns yellow or brown in early spring. If spray is the primary means of salt deposit, discolored needles are soon masked by the new year’s growth. However, if salt is also excessive in the soil, the new needles may die as chloride ions accumulate in them. If this happens for several years in a row, it can be fatal to the tree. In cases of severe or accidental salt damage to the soil horticultural gypsum can be added to possibly neutralize the harm.

Be careful and try to stay slip-free this winter while keeping your plants healthy. And keep growing.

Andrew Messinger has been a professional horticulturist for more than 30 years. He divides his time between homes and gardens in Southampton, Westchester and the Catskills. E-mail him at: Andrew@hamptongardener.com. The Hampton Gardener is a registered trademark.