Broadleaf evergreens are most easily affected by low temperatures and heavy wind, but other plants can succumb as well. Plants in sheltered and shaded sites deal with sudden temperature drops, but plants in open and sunny locations are especially vulnerable.
In these conditions, needles, stems, buds, and leaves give up moisture that cannot be replaced when the ground is frozen, leading to leaf burn (when the midsection of leaves become overheated and damaged) and dieback (when twigs and seedlings die leaving the main plant vulnerable).
Protect tender newly planted and exposed plants from the wind with a simple barrier of burlap, ground cloth, or row covering (sold at nurseries) stapled to sturdy posts.
Pound 6-foot lengths of 1- by 2-inch lumber securely into the ground and attach the fabric with a staple gun. Leave space at the bottom to allow air circulation.
Larger specimen plants can be wrapped in their entirety with burlap, cinched, and secured with twine.
The chemicals that make up commercial salt for snow and ice removal are toxic to almost all plants, including lawns. The spray created by traffic can become airborne, affecting trees as well as shrubs and turf. Damage includes bud and twig dieback and, in conifers, extreme needle browning.
Create salt barriers with burlap stapled to sturdy posts. Be sure to cover the base of the plant -- weighing down with mulch, soil, or rocks -- as this is where most salt accumulates. Consider using urea (a common fertilizer that's nontoxic to plants and available at garden centers) as snow melts.
Additionally, plants that go into winter in good health are better able to withstand damage. Keep plants well watered, mulch to prevent water loss, and add organic matter or gypsum to help leach sodium from the soil.
The warmth of the sun can cause sap to flow, especially when bounced off glass, brick, and other surfaces. Thawing can also combine with frozen soil conditions to cause winter burn (when leaves brown because of a rapid temperature change) and ruptured cells within the plant, leading to cracks and splits in the trunk and branches. Newly planted, thin-barked trees can suffer sun scald in such conditions, and fungus can grow.
Tree wrap made of corrugated paper helps protect newly planted trees.
Starting at the base, wrap several layers snugly around the trunk, moving upward with generous overlap. Pull the wrap away from the tree as you go for a tight fit. Finish with several layers as the trunk meets the the first layer of branches. Secure it well with tape or twine.
It's important to remove the wrap in early spring. Do this every year until bark begins to roughen, usually in about 3 to 5 years.
Fluctuations of temperature accompanied by the freezing and thawing of frost can cause heaving (a partial uprooting of plants) and kill freshly planted specimens. This is especially true of annuals, such as pansies and kale. The same holds true for late-planted perennials and even shrubs that are slow to establish roots in the surrounding soil.
Applying mulch after the soil has cooled down helps the soil maintain a constant temperature. This will help prevent plants from being heaved when then the temperature changes.
Mulch also helps maintain soil moisture. You can fill cages of chicken wire or hardware cloth with pine straw, leaves, mulch, and even loose compost. But, be aware that you can create a habitat for mice and other vermin -- poke holes in the pile every few weeks or turn the pile once a month.
Soft, powdery snow can create a winter blanket that helps insulate the landscape and is a great source of moisture when it thaws.
However, heavy wet snow and ice can pull the limbs of trees to the ground, in some cases snapping them. If left unattended, these bent limbs may never spring back, permanently altering the desired shape of the plant.
The shape and character of a plant will help dictate how to protect it from snow and ice. Narrow and columnar plants can be tied together with twine so the weight of precipitation won't split them apart. This can be done within the twiggy structure of the plant so it's almost invisible.
Snow cascading off roofs can have a disasterous effect. Simple snow sheds can be constructed from 2- by 2- inch lumber and outdoor grade plywood. The shed takes the brunt of the snow's weight, saving the plant from being snapped or pulled apart.
Conifer branches can create a beautiful blanket for a perennial garden.
The branches' supple nature can keep plants from snapping under the weight of ice and snow, protecting them from the effects of winter sun and wind.
Remove the conifer branches in spring, before they drop their needles.
The use of an antidessicant spray can help protect newly planted broadleaf evergreens from winter burn. It must be applied after the weather cools and must be reapplied as noted on the product label.
Note: Antidessicant sprays protect with a thin layer of wax, plastic, or resin, depending on the spray. Find it at nurseries.
Plastic netting that's designed as deer fencing or for trellising can be used as an effective binding for shrubs. Plastic netting comes in a range widths. It's easy to apply and from a distance, blends with the landscape. Look for 1-inch bird net at home-improvement store garden centers.
By Bill Mills, Cottage Living