Extreme winter wind is a factor when choosing your landscape plants. It’s not decreasing temperatures such as windchill that’s the issue. Plants are generally at ambient air temperature so increasing wind isn’t stripping more heat from the plant as it would with something that is warmer such as human skin. In fact, wind can increase ambient temperature by mixing colder air that has settled in lower areas like valleys.  

The risk to plants from wind is that it increases water loss from the foliage. This is a concern for evergreen plants, especially newly planted ones. If water loss becomes too severe in the winter, desiccation of the foliage occurs. This is called winter burn which can lead to foliage injury and when more severe, plant death. 

During the winter, an evergreen will continuously loose water from the foliage. When the ground is frozen, the evergreen can’t take up more water to replace what it’s lost. Faster winds and low humidity increase water loss. An additional factor that can increase susceptibility to winter burn is warmer temperatures when the ground is still frozen. When winter conditions include frozen ground, high winds, very dry air, and/or warmer temperatures, evergreen plants are at risk for winter burn. A windy day at 60˚ in February after long term cold temperatures may feel great to humans but can be a critical situation for evergreen plants. This is a guide to help you understand the effects on plants of extreme winter conditions that can cause winter burn and to help prevent it.

Symptoms – Evergreens in the landscape that have winter burn injury will appear normal and green until temperatures warm in the spring. It’s then that the affected foliage will begin to turn brown.

• Browning will occur on sides receiving prevailing winds and/or warming from the sun during the winter and early spring, usually south to west sides. 
• Needles will look brown on tips and depending upon severity will turn completely brown, potentially including whole branches and sides of the plant.
• Broadleaf evergreens such as Holly and Rhododendrons will have browning on the leaf margins. If windburn is more severe, whole leaves, sides of the plant, or the whole plant will be affected.

Prevention – Some plants have adapted to reduce water loss over the winter so may not need any intervention to prevent winter burn once they are established in the landscape. However, even if you are installing evergreens that are less prone to winter burn, those plants may need protection for the first several years after installation. Here are some winter burn prevention tips.

• Recognize winter conditions at the site that may increase the likelihood of winter burn on evergreens before installing new plants. It’s easier to change the plans or the plants before the installation occurs.
• Protect newly installed evergreens for the first several years after planting regardless of wind tolerance.
• Maintain optimum soil moisture through the fall until the ground freezes. If evergreens go into winter under dry conditions, they are more prone to winter burn. 
• Install wind breaks to help reduce wind on more sensitive evergreens. This can be burlap, fencing, hedges or other structures that are natural or otherwise to slow wind. Make sure if wrapping burlap directly on evergreens for wind protection to remove it when temperatures warm, reaching 40˚ consistently.
• Avoid pruning or fertilizing that would push new growth late in the growing season. New growth that hasn’t had time to harden off in the fall will be more prone to winter burn.
• Avoid installing evergreens, especially broadleaf evergreens, that prefer shade into sunnier locations. Winter sun can increase potential for winter burn.
• Be cautious when installing evergreens late in the season. There will be little to no time for root establishment. More roots equal more water storage which helps reduce winter burn.
• Choose plants that are cold hardy to your zone (See our “Extreme Conditions-Cold Hardy Guide” Information Sheet). Plants that are marginally hardy in the zone you are planting in will not be as well adapted to local winter conditions.

Plant Selection – Factors to consider when choosing plants.

• Look at what plants are thriving in your area. Native plants and plants that have adapted to a similar climate as the area you’re planting in will be more successful.
• If you choose to install a plant that is less adapted to your winter conditions, yearly fall preparations will be needed to keep them healthy. 
• Zone hardy deciduous plants don’t suffer winter burn. These plants may be a better choice in windy locations where evergreens would be susceptible to winter burn.

*This is a quick list of suggestions. It does not imply availability and there are many more possibilities not listed here. Please, come in and speak to our nursery staff who would be happy to supply additional information. See our “Extreme Conditions-Cold Hardy Guide” for more plant suggestions.

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