You could say that evergreens are the stars of cold weather, instantly infusing drab winter landscapes with color and texture. When well sited, watered and fed, most can stand up to the harshest of conditions. Still, some evergreens are less equipped than others to battle icy winds and harsh winter sun. These are the plants that can benefit from a little extra TLC to prepare them for colder temperatures.
Without proper preparations, cold weather can spell disaster for evergreens. Here are steps you can take now to fortify your most vulnerable plants for winter. HINT: The most important step is to water.
WATER YOUR PLANTS
The most important thing you can do to prepare your evergreen shrubs and trees for winter is to water them. And that means making sure they’re well hydrated beginning in early fall, a time when many people stop watering.
Rainfall can help with the job, but if you experience a dry spell it’s important to water your evergreens and continue to do so regularly until the soil freezes. Plants will hold on to the water and use it throughout the winter.
The most important thing you can do for your evergreens is to water them
Watering is crucial because all evergreens, and especially broadleaf varieties like rhododendrons and hollies, lose moisture from their foliage in a process called transpiration. Once the ground has frozen, it deprives plants of water, making it impossible for them to replace what is evaporating. This can lead to a common type of winter injury called desiccation, also known as ‘winter burn.’
Signs of desiccation can begin appearing as early as mid winter, when leaves of a plant may turn brown at the tips or several branches start to dry out or die. (This kind of damage typically shows up on the side of the plant that faces into the wind or has a southwestern exposure.) Other plants will hold on to their green color until spring or early summer when they begin to push new growth. Then their leaves will suddenly turn brown, start to curl and fall off.
TO DO: “Winterize” your evergreens by deep watering, which promotes deep rooting of plants and shrubs. Water them every other week, making sure the soil is moist to a depth of between 12 to 18 inches. Do this until the ground freezes.
PROTECT WITH SPRAY
Evergreens that are prone to desiccation, especially the broad-leaved varieties, often benefit from a little help in the form of spray. Anti-transpirant (or anti-desiccant) sprays, readily available at nursery and hardware stores, can protect tender leaves and stems by reducing water loss during times of plant stress.
Sprays provide a protective, film-forming coating that slows down moisture loss and protects plants from drying out. The transparent layers wear off gradually without interfering with plant growth or respiration.
In the winter, most sprays can remain effective for up to four months. Proper timing is key: it’s best to spray your plants in the morning when temperatures are above 50 degrees so the product has time to dry. You’ll need to reapply the spray once or twice during the winter.
(By the way, the sprays work great on indoor holiday greenery, too.)
TO DO: Spray plants once in December and again in February to prevent water loss and protect their leaves.
BUILD A SCREEN OR SHELTER
Shelters and screens are great for smaller shrubs that you’d like to protect from excessive wind, falling snow and road salt damage. Although you can buy ready-made frames at the store, burlap, some lumber and a few stakes are really all you need to make one on your own. Steer away from plastic, though. You could cook your plants.
To make a screen, drive the stakes into the ground on the windward side of the plant or on its southern exposure, where it is at greater risk of exposure to swings in temperature. Staple the burlap to the stakes.
To make a shelter, place stakes all around the plant to form an A-frame. Stretch the burlap across the structure. Or, you can attach plywood panels to the stakes to create an even sturdier frame.
TO DO: Take an inventory of your landscape and pinpoint any plants that may be vulnerable to winter stress. Evergreens that face the wind or have a southern exposure may need screens to guard against winter burn. Pay particular attention to plants that are located under the roof line, where falling snow could be a hazard. A-frame shelters are great at shedding heavy snow and ice. For a great tutorial on how to build screens and shelters, go to thisoldhouse.com.
TIE THEM UP
Evergreens can be damaged by heavy snows or ice storms that snap their branches. Foundation plantings can be particularly vulnerable, since they are often exposed to snow falling from the roof. A good way to protect your plants is to tie them up to give them a little extra support.
Using heavy twine or string (I use green-colored twine so it doesn’t show), begin by attaching the twine to the base of the plant and wind the plant up, drawing in clumps of branches as you go. Once you end up with a tight spiral, you can leave it alone or cover the shrub with burlap.
TO DO: Tie up foundation plantings like boxwood and azaleas to prevent against breakage and dust snow off of fragile bushes with a broom or by shaking to make sure it doesn’t accumulate.
Mulching in the fall is a great way to protect your evergreens from fluctuations in soil temperature and damaging moisture loss. Mulches are proven water conservers; able to reduce moisture loss anywhere from 10 to 50 percent. Adding a protective layer of mulch insulates your plant and prevents water from from escaping from the subsoil.
TO DO: Depending on how big the root zone is, make a 3- to 6- foot diameter circle around the shrub or tree and apply a 2- to 3-inch layer of mulch, making sure to mix in some organic materials to add nutrients to the soil.
A word of caution: don’t pile the mulch up around the plant crown or tree trunk. This could cause the plant to rot and die. A distance of six inches or more is a good rule of thumb to follow.
Even if your evergreen looks bad, try to refrain from pruning brown foliage or branches until after the winter. Wait until the spring or you risk further damaging the plant.