Winter Burn

In Plant Health Care, Winter by Forest Keeper3 Comments

Cape Cod South Shore Winter Burn Damage

Winter Burn on Rhododendron

Wow! It has been pretty cold out there the last few days. It seem like the winter temps. here on Cape Cod are all over the map. For example, Jan.17: Low of 11 and high of 23. Then for the rest of the week it’s in the 40’s. Huh? Okay, then on the 24th, I’m sure we all remember: a whopping 2 degrees for most of the day with a high reaching all the way to 11! BRRRR! But then wouldn’t you know it, the rest of the week was temps above  freezing. Good ‘ol Cape Cod weather.

Browning effects of winter burn on shrub

Depending on location and current conditions, winter burn can cause considerable damage to your landscape shrubs.

Well this fluctuation actually takes it’s toll on the trees and shrubs. Especially during drastic winters, such as this one has been. Very often in the early spring many evergreen plants will be spotted with brown and wilted leaves. This damage is often called winter burn. Winter burn injury is leaf damage that is caused by cold winds which dry out the leaves. Winter burn injury can take place whenever the soil freezes and wintry winds blow, drawing moisture from leaves. Plant roots can not uptake water from frozen soil to replace the losses experienced in the leaves.

Winter burn can also occur when the air temperature periodically rises. The warmer temperature causes the leaves to begin the process of transpiration, the release of moisture through small pores on the surface of the leaf. The longer these conditions exist, the more moisture is lost and death of leaf tissue results. Plants that hold their leaves (evergreens) over the winter are vulnerable. Broad leaf types are more susceptible than the needle type evergreens due to the larger surface area of their leaves. This kind of damage is a common problem here on Cape Cod as our winters tend to be quite windy with unpredictable temperatures.

arborvitae wrapped to protect from drying winds

Arborvitae wrapped to protect from drying winds.

To prevent this damage make sure you water your evergreen trees and shrubs into the fall until the soil freezes.

You May also want to create a barrier around plants that are susceptible to burning, including wrapping them in burlap.

Another tool in helping to prevent winter burn is to apply an anti-desiccant  to any susceptible plant material in the early winter when soil temeraptures start to drop. Anti-desiccant is a spray that creates a barrier over the pores (stomates) in the leaves. This barrier allows the plant to breath but reduces water loss through transpiration. Generally this treatment is applied to the foliage as a liquid. Anti-desiccant applications are generally made in late November- December, and again in late January. One late fall application is not enough, and I have found that relying on this measure of protection alone is often not enough. Usually a combination of these approaches together  afford good protection.

Here is a list of some (but not all)evergreen plants that can be susceptible:

*Southern Magnolia
*Rhododendrons
*Azalea
*Cherry Laurel
*Mountain Laurel
*Japanese Pieris (Andromeda)
*Aucuba
*Ivy
*Leucothoe
*holly

Comments

  1. Thank you for an informative article.
    I planted 7 laurels around my property in Mt Washington Valley NH last fall. 2 came through with no damage, the 5 in a group got some winter burn. Several articles I read said to hold off pruning until after flowering, but my instinct tells me to get rid of the damage as soon as possible. I will be wrapping them next winter (let’s hope we have a winter), should I use an anti-desiccant as well? I wouldn’t be unwrapping them in Jan to apply a late season coat though.
    Thank you. B

    1. Author

      Using an anti desiccant as well wrapping would certainly help. And yes, I agree that you wouldn’t necessarily h ave to unwrap the plant to do apply another coat .
      As far as the pruning, I’m not sure but it seems like it would be fine to prune out the damaged material now instead of later. Did the articles that you read explain why you should wait?

  2. We advise our clients to water their needled and broadleaf evergreens as much as the plants can take in the fall, before the ground freezes. The idea is to usher plants into winter with their tissues as fully hydrated as possible, so that when the sun warms the leaves in late winter and transpiration begins, there’s enough moisture in the foliar cells that the leaves don’t burn. It really does make a difference; plants that go into winter with extra watering — especially after a dry fall like the one we just had — stand a much greater chance of not getting winter-burned foliage than those that don’t get watered thoroughly in anticipation of those warming temps in February and March. Those people with irrigation systems need especially to get the message, as the lines will often be shut and blown out in October, well before the onset of ground-freezing temps in Massachusetts, which in 2013 happened in late November/early December.

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