Winter is the perfect time to cozy up indoors with a hot drink and a warm blanket. Unfortunately, your trees and shrubs don’t have this same luxury. Landscape plants remain outdoors all year long, exposed to the dry, chilly air and low temperatures. This harsh weather can increase the rate of water loss from your plants’ foliage, all while reducing the amount of water they take in from the ground. The result is winter burn, which can kill your plants if not prevented.
Winter burn is a prevalent issue for evergreens. But what is winter burn, and how can you prevent it? This article will teach you all you need to know about winter burn, including what it is, what it looks like, and how to protect your plants from it.
What Is Winter Burn?
Winter burn (also known as winter desiccation or winter kill) occurs when an evergreen plant loses more water through its foliage than it picks up by its roots. Evergreen plants, which keep their foliage year-round, lose water through their foliage through a process called transpiration. Normally, evergreens absorb enough water in the soil to replace the water lost through the foliage. However, the weather conditions in winter make it much harder for this replacement to happen. This causes evergreens great distress. Severe cases can lead to the death of the affected foliage, branches, or even the entire plant.
Multiple weather factors affect the severity of winter burn. They include the following:
- Wind: Wind is the most significant variable affecting the rate of transpiration. The air is much drier during wintertime because cold air cannot hold onto much moisture. This dry wind picks up the moisture from your evergreens, increasing the rate of transpiration.
- Sun: Though we often associate winter with gray, cloudy skies, some regions experience cloudless, sunny days paired with bitter temperatures. The more light a plant absorbs, the more water it loses. Therefore, evergreens that are in direct sun throughout the winter will experience an incredible amount of water loss.
- Frozen soil: Transpiration is not an issue throughout most of the year because plants replace the water they lose by absorbing moisture from the soil. But your plants cannot draw up water if the soil is frozen. Frozen soil can dry out plants very quickly. It is probably the most common reason why plants experience winter burn.
- Drought: Much of the world experienced an intense summer of record-breaking heat and widespread drought. If you were unable to water your plants adequately during this extreme weather, then your plant may still be stressed out from the ordeal. Plants that have experienced drought stress at any point in the year have a harder time storing water to catch up. Therefore, they will not be adequately watered when winter arrives, which makes them much more susceptible to winter burn.
What Does Winter Burn Look Like?
Without proper moisture, trees and shrubs experience significant damage. This damage can be slow to appear, but it can be quite significant when it does. So how can you tell if your evergreens have winter burn? Below are four common signs of winter burn on evergreens.
- Brittle foliage and twigs: Since the plant loses water through its foliage, the foliage and twigs will become very dry and brittle.
- Browning/discoloration of foliage: Most species will exhibit browning of their foliage after significant water loss. In some cases, the foliage will turn yellow or reddish instead. The discoloration usually starts at the edges/tips of the foliage and then covers the entire needle/leaf over time.
- Needles fall off easily: It’s normal for evergreens to shed some needles during the winter. But plants suffering from winter burn will shed an enormous amount of foliage, particularly foliage that exhibits the other two symptoms above.
- Most damage is on south or windward sides: There are situations where the three symptoms above could be signs of another issue. However, a telltale sign that this may be winter burn is if most of the damage either occurs on the south/southwest side of the plant or on the side that gets the most wind. This shows that the damage is caused by the weather and therefore is very likely to be winter burn.
Unfortunately, many evergreen owners don’t notice the extent of the damage until late in the winter when it is too late to do anything. Once winter burn has set in, there is little you can do to reverse the damage. In cases where only small parts of the plant were affected, the plant may be able to recover throughout the rest of the year. However, severe winter burn can damage huge portions of the plant, causing irreversible damage and plant death.
Therefore, it’s best to prevent winter burn from occurring rather than hope to fix it once you see the signs of damage. Unfortunately, symptoms of winter burn may not show up until spring, and then it will be far too late to do anything about it.
What Plants Are Affected By Winter Burn?
Winter burn primarily affects evergreens. By wintertime, deciduous trees and shrubs have shed their leaves, so they don’t have to worry about transpiration. However, evergreens hold onto their foliage all year round, meaning they still lose a ton of water in the winter.
Many landscape plants are affected by winter desiccation each year. Below are the plants that are most susceptible to this problem.
- Coniferous evergreens: Coniferous evergreens have the classic evergreen needle foliage. These include arborvitae, cedar, juniper, pine, and Hinoki cypress. Winter burn shows up in these species as brown (or sometimes yellow), brittle needles that eventually fall off the tree. The coloring starts at the tip but eventually spreads throughout the entire needle. Conifers are usually perceived as hardy and sturdy plants, but even they are not impervious to the damage caused by winter burn.
- Broadleaf evergreens: Broadleaf evergreens are even more susceptible to winter burn because of their foliage. Their foliage is broader and has more surface space, which means they exhibit a higher rate of water loss. When winter burn appears in broadleaf evergreens, the edges may brown first before the entire leaf changes color. Some common broadleaf evergreens that experience winter burn include rhododendron, boxwood, azalea, and holly.
- Plants with tender stems: Other plants and shrubs with tender stems, such as hydrangea or rose canes, are susceptible to winter damage. These plants don’t exactly experience winter burn like the other species in this list, but they can become damaged from the harsh winter elements. They need proper preparation and protection in winter to prevent damage and exhibit better blooms and growth in the spring.
What Can Be Done To Prevent Winter Burn?
Preventing winter burn on evergreens requires forethought and planning. You need to ensure they are properly protected from the harsh elements and are healthy enough to endure the long season. Below are a few tips that will help you prepare your evergreens this winter.
Many people choose to apply anti-desiccant or anti-transpirant sprays to protect their plants’ foliage. These sprays add a waxy coating to the foliage that reduces transpiration. The coating keeps the water in place, meaning your plant won’t lose water or need additional waterings to stay properly hydrated throughout the winter.
However, there are some cautions to know about when using anti-desiccant sprays. First of all, if you use them too soon, you could do more harm than good. In late fall, evergreens send much of the water they hold in their foliage down to their roots. If you apply an anti-desiccant spray before this process occurs, you may trap too much water in the foliage. This can cause cell damage throughout the winter as the foliage cells expand and contract with weather changes. Therefore, if you choose to use anti-desiccant sprays, wait until late fall or early winter to use them.
Also, just because anti-desiccants are the easiest option to prevent winter desiccation doesn’t mean they are 100% effective. These sprays do not prevent water loss, only reduce it. The effectiveness of these sprays varies, and they aren’t a good option to use regularly. There is no guarantee these sprays will work as promised, so you may need to include another protection method in your strategy.
Protect Your Evergreens From The Elements
Winter desiccation is caused by harsh winds, a lack of precipitation, and any other weather elements that encourage transpiration. Therefore, the best way to prevent winter burn is to protect your evergreens from these elements.
There are a few ways that you can do this. First, it is important to reiterate that most winter burn damage occurs on the south, southwest, and windward sides of your plants. These are the areas you should put the most effort into protecting. To protect these areas from harsh winds and other elements, construct a barrier by attaching burlap (or similar material) to posts and placing them around your trees and shrubs. This is a particularly effective strategy to prevent winter burn on boxwoods as well as arborvitae winter burn.
However, if your evergreens have exhibited winter burn damage on all sides in previous years, then you will want to surround the entire plant with a barrier. When creating this barrier, keep the top open to allow some air and light penetration.
You should also consider adding mulch to the base of your plants before winter arrives. Mulch acts as an insulator that keeps soil temperatures higher. This prevents the soil from freezing and allows your plants to absorb its moisture. This is a particularly effective strategy to prevent Hinoki cypress winter burn, especially if your Hinoki cypress has shallow roots.
Finally, if you have any pine boughs or Christmas tree greens, you can prop them over your evergreens to protect them from the winter wind and sun. They can also catch snow, protecting your plants from any potential damage caused by it.
Keep Plants Thoroughly Watered
Another way to prevent winter desiccation is to ensure your plants are at their optimal health before the harsh weather sets in. This means ensuring your plants are adequately watered. However, you have to be strategic about this.
Many people make the mistake of waiting until the late fall to prepare their evergreens for winter. This is far too late in the season to start watering. You won’t have the time to adequately hydrate your plants before winter sets in, so they won’t have enough moisture to prevent drying out.
Instead, you need to water your evergreens throughout the entire growing season, not just a few weeks before winter. Once summer ends, you should decrease watering slightly in September to encourage hardening off and then water thoroughly again in October until freeze-up.
Many people are eager to prune their evergreens and shrubs once the growing season is over. However, pruning anytime after August makes your plants susceptible to damage. When you prune plants, you induce the growth of new foliage. That new foliage is tender and far more susceptible to damage from the elements than hardier older growth. Therefore, don’t prune your evergreens in the fall; wait until spring when the winter weather has passed and the growing season is about to begin.
Take A Multi-Faceted Approach
It’s important to stress that there is no one size fits all solution to protecting your evergreens from winter burn. One method may be enough for some plants but may not work for others. That’s why you should adopt a multi-faceted approach when it comes to preparing your landscape for winter.
For example, many people believe that just spraying their plants with anti-desiccants is enough to protect their evergreens from winter burn. But as mentioned earlier, these sprays are not 100% effective, so you’ll need to incorporate another strategy (such as creating a barrier). Likewise, large shrubs (like rhododendrons) and trees cannot be covered entirely by burlap barriers. Therefore, you will need to complement these barriers with another protection method, such as an anti-desiccant spray or watering your plants in late fall.
The exact methods you use will depend on the types of plants in your landscape. However, you essentially want to incorporate both protection and care elements in your strategy. This will ensure your plants are protected but are also healthy enough to withstand the harsh winter elements.
Contact Us For Help Preventing Winter Burn
All the above precautions will ensure your evergreens are at their best to handle the winter elements. However, creating barriers and preparing your plants for the harsh winter can be an undertaking. Furthermore, it’s not always easy to know if you’ve prepared your landscape adequately, and you can’t fix the damage of winter burn once it sets in.
Hiring a professional ensures the job gets done perfectly every time. A professional will know exactly what your evergreens need to prevent winter burn and work with you to come up with a multi-faceted strategy to prepare your landscape for winter. So, if you need some help this season, then contact Better View Landscapes. We can ensure your plants are protected and won’t suffer from the harsh winds and cold temperatures this season. To learn more about how Better View Landscapes can help, check out our website by clicking this link.