Last week, it snowed overnight. The heavy flakes quickly blanketed the landscape, transforming my garden into a field of glistening white. But the next morning, I woke to discover my boxwood splayed open under the weight of it, a pile of broken stems at their base. Snow is beautiful, but it can be tough on evergreens.
In fact, without proper preparation, cold weather can spell disaster for plants; especially broad leaved species like boxwood, rhododendrons and hollies. Here are five steps you can take now to your protect your evergreens from winter damage.
WATER IN WINTER
During the cold months, we often take time off from gardening. But drought doesn’t take a winter break. Your evergreens may be suffering from drought stress without your knowing it.
One of the most important things you can do to protect your evergreens is to water them. And that means making sure they’re well hydrated beginning in early fall, a time when most people stop watering.
Sure, rainfall can help with the job. But if you experience a dry spell, it’s important to water your evergreens regularly and continue to do so until the ground freezes. The plants will conserve the water and use it throughout the winter.
All evergreens lose moisture through their leaves in a process called transpiration. When the ground freezes, however, they’re unable to replace what is lost through evaporation. This can lead to a common winter injury called winter burn.
Signs of winter burn include leaves or needles that have turned brown or yellow. Often, the browning advances inward, with broadleaf evergreens showing browning first on leaf edges followed by browning of entire leaves. Damaged foliage typically starts dropping off in the spring and continues through the summer as new leaves develop.
TO DO: Water your evergreens throughout the fall until the ground freezes. This will help them develop a strong root system that will sustain them during the colder months. During dry spells, water them during winter when temperatures climb above 40 degrees.
USE ANTI-DESICCANT SPRAY
Evergreens that are prone to desiccation (especially broad-leaved species like rhododendrons, boxwood and hollies) can be protected from winter damage with anti-desiccant spray. This can safeguard vulnerable leaves and stems by reducing water loss during times of plant stress.
Sprays provide a protective waxy coating on leaves that slows down moisture loss and keeps foliage from drying out. The transparent layers wear off gradually without interfering with plant growth or respiration. Most sprays remain effective for up to (four) months.
By the way, these sprays work great on indoor holiday greens, too.
TO DO: Protect your evergreens by spraying them once in December and again in February to coat their leaves and stave off water loss.
PROVIDE SOME SHELTER
Shelters and screens are great for smaller evergreens that may be vulnerable to winter damage from heavy snow, excessive wind, or road salt damage. You can buy ready-made frames at the store. But a few stakes, staples and burlap are really all you need to get the job done. Steer away from plastic wraps, though, which can cook your plants.
To make a shelter, place stakes around the plant to form an A-frame. Stretch the burlap across the structure. Or, attach plywood panels to the stakes to create an even sturdier housing.
To make a screen, drive some stakes into the ground on the windward side of the plant or on its southern exposure where it’s at greater risk of exposure to temperature swings. Staple the burlap to the stakes.
TO DO: Take an inventory of your plants and determine which might be vulnerable to winter stress. Evergreens that face the wind or have southern exposures 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 ice and snow.
TIE UP FRAGILE LIMBS
In winter, evergreens are easily damaged by heavy snows or icy winds that can snap their branches. Foundation plantings are particularly vulnerable, since the shrubs are often exposed to snow falling from the roof. A good way to protect your plants is to tie them up. This gives them some 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 in the center and wind your way up, drawing in clumps of branches as you go. Once you create a tight spiral, you can leave it alone or cover the shrub with burlap.
TO DO: Tie up foundation plantings to guard against breakage and remember to dust snow off of fragile shrubs so it doesn’t accumulate.
INSULATE WITH MULCH
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.
TO DO: Depending on how big your plant’s 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 back to the soil.
Don’t pile the mulch up around the plant’s crown or tree’s trunk, however. This can lead to root rot. A distance of six inches or more is a good rule of thumb to follow.
WAIT TO PRUNE BROWN FOLIAGE
Finally, even if your evergreens look bad, try to refrain from pruning brown foliage or dead branches until after winter. Wait until spring or you risk further damaging the plants.