They say you must understand your enemy to stay ahead

The Hazards Of Old Man Winter
Knowledge Equals Protection For Your Yard
By Jim Kohut, Staff Writer

They say that knowledge is the cornerstone of a good defensive strategy, and that you have to know your enemy to stay two steps ahead of them. If you're a northern homeowner like me who takes great pride in your yard and gardens, then Old Man Winter is our common enemy, and he's a'coming to wreak havoc on our trees, shrubs, flowers and lawns some time soon!

In this info sheet, I want to support the valuable instructions you're getting on winterizing your yard and gardens with some very important background information on the specific threats that our northern winters pose. By understanding the hazards our plants and structures face in winter, you can better understand why we take the measures we do to protect them.

So let's look at the hazards that this coming winter will throw at us by the specific elements in your landscapes, along with some pointers for their prevention and protection.

Trees & Shrubs

Overwintering trees and shrubs is probably the greatest challenge northern homeowners face. Because the majority of their growing parts remain exposed and unprotected over the course of the entire winter season, they face all the extremes of the elements that winter can throw at them. If you have any trouble appreciating just what they are asked to face in winter, imagine yourself standing outside in your yard each and every day of this coming winter buck naked, through the wind and snow and sleet and frigid nights, and you'll get the picture.

Cold Temperatures - The living cells of the trees' bark and buds have to survive the winter fully exposed to the coldest temperatures that winter can throw at them, but without freezing. They do this by empoying an internal "antifreeze" solution which prevents ice crystals from forming and rupturing the cell membrane, which is what ultimately kills the tissues (it's the same with frostbite in humans). But much like the antifreeze in your car, it's only effective down to a certain minimum temperature, and below that, the cells will freeze and start to die. This is one of the core indicators of hardiness, and there's not much a homeowner can do to protect trees from low temperatures other than to select plants which are known to be hardy in that specific climate. I can say from experience, though, a healthy tree going into winter is far more likely to make it through than a stressed one. For smaller shrubs, though, it is possible to provide some insulation with snow or mulch.

Wind - This is an enormous challenge for exposed trees and shrubs. Wind accelerates the evaporation process which continues through winter. However, with the ground frozen, the plants are unable to replenish the lost moisture, and as a result growing tissues can die from dehydration, a process known as "dessication". This is particularly troublesome for evergreens which are required to keep their leaves fully hydrated right through winter, although even deciduous plants experience moisture loss through their stems and branches. The key to protection is shelter from the wind, whether it be artificial (e.g. the side of a house), natural (e.g. against a dense forest) or temporary (e.g. a burlap screen erected on the windward side).

Sun - Sunlight can be a real problem for exposed plants, especially in late winter when the sun is higher in the sky and yet the temperatures are still bitterly cold. The biggest problem occurs when the direct sun warms parts of plant's growing tissues to above the freezing point, but then rapidly disappears behind some obstacle. The cells adjust to the warmer temperatures but are then suddenly exposed to the full cold air temperatures once again, and if their antifreeze mechanisms can't react fast enough, ice forms and the cell dies, a condition known as "sunscald". The problem is made even worse is when sunlight is reflected off a white south or west-facing wall or fresh white snow cover. The best solution is to shade the sensitive parts of trees (usually the trunks) with reflective tree wraps, white fabric or white latex paint, all of which will reflect the sunlight and prevent the warming from occuring in the first place. Sunlight is also a threat to evergreens and can result in dessication which manifests itself as needle browning in spring; as with wind, a burlap screen on the south and west side will alleviate the problem.

Animals - Without question, animals are the leading cause of winter injury to trees and shrubs. Deer, rabbits, mice and voles become starved for food when it is covered by snow, and are forced to turn to your precious trees and shrubs as food sources. If you're lucky, they'll just eat the tender young branches, which may disfigure the plant somewhat or eliminate any spring flowers. In the worst cases, however, they can cause severe damage, and when they gnaw at the bark in a ring around the trunk of a tree (known as "girdling"), it can be fatal to the tree. There are a number of protections worth considering which deter animals; mechanical (e.g. tree wraps, fencing, mesh), repellent (e.g. applications of malodorous or bad-tasting substances), and others.

Ice Storms - Many regions of the North are susceptible to infrequent and yet severe ice storms. As ice, sleet and slush accumulate on branches, they exert an additional mechanical load which can severly stress them to the point where they can no longer support the added weight, and they come crashing down. Not only does this result in the severe disfiguration or loss of the tree, it can also cause massive destruction to your home and yard on the ground. If you live in a region with a history of ice storms, you are well advised to plant trees that are known to have strong branching, and to stay away from those with weak wood and narrow vertical branch angles.

Early Frosts - Probably the most indisious of winter's hazards actually occurs in late fall. The most important trick to succesfully pulling a tree or shrub through the winter is to ensure that it goes into winter as healthy as possible. Unseasonally early fall frosts can damage growing tissues which haven't properly hardened in preparation for winter yet, and these tissues are then more susceptible to the other hazards of winter. There's not much homeowners can do to prevent this, other than locating trees and shrubs out of lower areas where frosts tend to accumulate, and doing everything possible to encourage the hardening process.

Gardens

The primary winter threats to gardens are to the perennials you are trying to overwinter. While these can be subjected to the full range of elements that exposed trees and shrubs face, gardens are far more likely to be protected by the insulating effects of snow, or manually with some strategically applied mulch. Still, Old Man Winter wants at them, so it's up to you to stop him!

Exposure - Beware of the exposed garden; this is the number one killer of perennials! In fact, the truth is, most of the perennials we grow in the North are not "hardy" in the sense that they could withstand our winters fully exposed to the elements. We are able to grow most of these because they are safely sheltered from the harsh conditions under a layer of snow, leaves or mulch. So if your garden is in a windswept area, or a region with little snowcover, be prepared for some human intervention!

Frost Heave - The freezing and thawing of the ground results in movement which can forcefully shift and crack the soil. While the roots of most mature trees and shrubs are strong enough to actually secure the ground from shifting, the roots of most perennials aren't. As a result, they can be torn apart or exposed to the elements, neither of which are conditions they particularly relish. Because frost heave tends to be worst in exposed locations, site your gardens where they are reliably protected by snow, and make sure they have effective drainage, especially in fall.

Spring Flooding - Winter snow may be a blessing when it comes to insulating against the extreme temperatures, but it can rapidly become standing water and even flooding come the spring melt. Many perennials, especially bulbs, strongly dislike excessive periods of standing water in spring; it can promote disease and rot. That's why it's always an exceptionally good idea to keep your gardens well-drained, slightly raised and away from lower parts of the yard where water tends to collect.

Animals - As with trees and shrubs, animals are responsible for some of the winter damage experienced by garden perennials. However, since only the crowns and underground parts of the plants are required to survive the winter, damage is often less severe. The biggest threat is from mice, voles and rabbits, which will dig into the ground to get at the tender parts of the plants; they seem to be particularly attracted to fresh, juicy bulbs (at least from my experience!). Try using animal repellents or wire mesh to keep them away from your cherished treasures.

Lawns

Lawns are living parts of a landscape, and so they face many of the same hazards as all the other plants you have welcomed into your yard. The only difference is, they make up the single largest plant mass in most suburban yards, so problems can appear exaggerated and obvious. Love them or leave them, our lawns are our pride and we don't like to have them looking bad come spring!

Ice - This is particularly damaging to lawns; it compacts them and severly delays their ability to recover from winter in spring. It can form as a result of either poor drainage or mechanical compaction of snow, for example from walking. The result is dead patches in spring that take significantly longer to green up. The solution lies in fixing the specific problems causing the ice; improving drainage, or discouraging walking across the lawn in winter. And for heaven's sake, don't intentionally turn your lawn into a skating rink unless you really don't care how it looks in spring!

Disease - Many lawn diseases are trapped underneath leaves, debris and even deep snow cover, sheltering them through the winter along with the grass to resurface and cause trouble once again in spring. The best way for a lawn to go into winter is disease-free and healthy; well watered, properly fertilized (a root-promoting fertilizer rather than nitrogen) and manicured. Again, keeping the lawn clean in fall will help to prevent these problems. Occasionally snow mold appears; this can be unsightly in spring but usually isn't fatal.

Animals - Mice and voles are the real threats when it comes to animal damage to lawns in winter. They can chew the grass right down to the roots, and carve out intricate tunnels that wind across your lawn. These become all too apparent in spring when the snow melts. Mouse and vole damage is not always fatal, but can severely retard the growth of a lawn in spring, leaving you with an unsatisfying lawn until summer at best, and serious damage at worst. They tend to build their nests in taller grass, perennial beds or piles of leaves and do the worst damage in areas of excessively deep snow cover. Here a cat comes in handy, or you can try other methods of control such as mouse traps, impregnated seed or poison. It also helps to keep your lawn cut short for fall, clean and free of leaves and debris.

Chemicals - Many of the chemicals we use in winter such as deicing salts and antifreeze are quite harmful to lawns, not to mention trees, shrubs and any other living thing that comes in contact with these materials. Not only are they a threat by direct contact, they can also be carried to remote parts of the yard in the spring melt runoff. Keep these chemicals as far away as possible from growing things in your yard, and do not allow them to accumulate over the lawns and gardens.

Hardscaping

When we think of preparing our yards for winter, we often think of our plants, because as living beings they are being asked to handle the vagaries of our winters in the extreme. However, our hard landscaping elements are also affected by winter hazards which can damage and degrade them, shortening their lifespan in the yard and rendering them unsightly. So, they warrant our attention and care as well.

Weathering - The same winter elements that threaten our plant friends in the landscape can harm our hardscape features. These include wind, sun, snow and ice. It's usually a combination of these stresses that wear down the surface features of our statuary, arbors, birdbaths, fountains, decks, patios, walkways and driveways. Paint can fade or be stripped, finishes can be eroded, and materials can tarnish or oxidize. The best thing to do is keep an eye on these features of your landscape and be cognizant of the proper maintenance procedures for each. Keep your wood products preserved and stained, maintain the finishes on your ceramics and metal elements, and replenish surfacing such as decorative mulch as required to give them a full and happy life in your yard.

Frost Heave - This same culprit which is a threat to perennials and some shrubs is a major threat to landscape structures, particularly those that sit on or in the ground. Fences, borders, edging, arbors, and posts which are installed in the ground are highly susceptible to frost movement and shifting which can not only throw them out of alignment but can even damage or break them as a result. It's a huge problem for walls, decks and patios, throwing them out of level and possibly compromising their integrity. Even more mobile structures such as statues, gazebos, birdbaths and greenhouses can be affected just sitting on the ground. For subsurface structures, the best option is to build them onto solid footings pounded or poured below the frost line for maximum stability. For structures that sit on the ground or shallowly in the ground, ensure optimal drainage by installing a deep layer of draining rock below the structures. And for major structures, consult a landscape engineer who is familiar with the winter effects of your climate.

Snow Loads - All structures are only able to withstand so much weight on them by their design. When that weight limit is exceeded by excessive snow or ice, they can break and come crashing down. When these structures are arbors, sheds, gazebos and decks, they can really present a safety hazard to you and your family. Properly engineered landscape structures will have snow loads take into account during the design phase, so that's a good reason to have these designed by professionals. If you have suspicions for whatever reason, consult with a landscape engineer or architect to have them evaluated for their safety.

Moisture Cracking - When water freezes, it expands. When water freezes inside of constrained spaces, it expands and then cracks whatever was containing it. So outdoor pails, buckets, barrels and pots should all be drained before freeze-up. But even containers which hold materials with a high moisture content are at risk. For example, ceramic, plastic or concrete planters are highly susceptible to cracking if the soil inside of them is allowed to freeze. These are best either emptied or left to dry out in fall and then moved indoors or into a shed or garage for the winter.

With this background, you should now be able to see the logic behind most of the winter yard care tips and information you'll find on Northscaping. This should also help you objectively weigh advice you see elsewhere, just to be sure it's relevant to you and your northern yard and gardens. The last thing you want is bad yard care advice from someone living in Southern California who's idea of winter is a "chill in the air"; remember, it's your yard that will suffer, not theirs!

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