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Should Trees be Wrapped in Winter?

Why do we wrap trees and shrubs in winter? It seems to be a northern tradition. Every fall we go out and wrap plants in burlap to keep them protected from winter weather. All the books and all the web sites tell us to do this, so it must be right? Let’s have a closer look.

Trees wrapped in winter

Should trees be wrapped in winter?

Why Cover Trees and Shrubs in Winter?

There are several stated reasons;

1) Keeps plants warmer

2) Reduces moisture loss

3) Keeps deer away

4) Protects from ice damage

5) Reduces salt damage

6) Looks good

7) Protects from sun

Let’s have a more detailed look at each of these reasons and then decide what approach we should use.

Keep Plants Warmer:

This topic has been dealt with in a previous post. See Are Wrapped  Trees Warmer in Winter for more details. Wrapping plants in winter does not keep them warmer.

Reduces Moisture Loss:

This topic was discussed in Keep Plants Warm in Winter . Reducing moisture loss is important for some plants and a wrap can reduce moisture loss.

Keeps Deer Away:

This is certainly true. Deer eat just about anything when they are hungry. They leave my Yew alone all summer and early winter. By late winter they come and have a meal. A wrap of burlap keeps them from eating the new growth from the previous year. I also cover some small shrubs with chicken wire if I suspect they will eat them (eg sumacs) until these plants get big enough to fend for themselves.

The wrapping in the picture above looks silly–only the bottom of plants are wrapped. But it is a good way to reduce deer damage provided the wrapping goes as high as a deer.

Protects From Ice Damage:

People who live in the north understand the damage an ice storm can cause. In a few hours branches of trees and shrubs can be covered with a very heavy layer of ice. The weight of the ice can break branches or bend them dramatically. Most deciduous plants will recover and fill in the broken spaces. Some evergreens, especially upright evergreens like junipers can be so severely deformed that they never look good again.

Wrapping with burlap can prevent ice damage. It keeps the branches close together so that the ice can’t bend them over.

Salt Damage:

Salt spray from the road can be damaging to some evergreens. Covering them can help.

Looks Good:

In most cases, the covered plants do not look good. The above picture is an extreme example. To be honest most coverings make your front lawn look terrible.

Protect From Sun

Most shrubs and trees do not need to be protected from sun in winter, but there is at least one group of plants that will benefit from such treatment. Some of the newer yellow-leafed evergreens, brown very easily in winter from drying and sun damage. This is mostly an issue for 2-3 years after planting. Once the plant is well established it is less sensitive to sun and drying. So if you plant such evergreens it is a good idea to wrap them, in winter, for 3 years.

Issues With Plant Covers

There are clearly some good reasons for covering your trees and shrubs, but there are also reasons for not covering them.

1) Moisture issues

2) Rodent problems

3) Sun scald

Moisture Issues:

Plant covers reduce wind and therefore reduce loss of moisture from the plant. The same covering however can also cause problems with too much moisture. Many plants that are native to cold regions of the world like to stay dry in winter. This includes most deciduous trees and shrubs, as well as all perennials. Excess moisture can cause them to rot.

Rodent Problems:

You have made a nice cozy spot for your plant and rodents think that is just marvelous. A nice place to spend the winter, and plant food to eat – better than the Holiday Inn.

Sun Scald:

Some coverings, like clear plastic, act like a greenhouse. When the sun shines the temperature increases significantly, and this can damage the plant. If the temperature gets too warm it can scald the plant. Lower warm temperatures make the plant think it is spring and they start to grow. A few days later it gets very cold again and the plant dies. Once a plant has cooled down for the winter it is best to keep it cold until spring.

Should You Cover or Not?

If plants are covered correctly, none of the above mentioned issues should be a problem. Covering plants does provide some benefit, however, I would suggest that except for the deer issue and the yellow leafed evergreens, very few plants need to be covered. If you don’t plant upright evergreens with very vertical branches, you really don’t have an issue with ice storms. If you select plants that survive winter in your zone you will not need to protect them. Spend a bit more time selecting your plants rather than spending time covering them each year.

I garden using a fairly simple philosophy. Make gardening easy and fun. Covering your plants is extra work. If you select a plant incorrectly and it gets damaged in winter or even dies, the solution is simple. Plant something else in it’s place. With many thousands of plants to choose from why struggle with a lemon?

References:

1) Photo Source: Buffalo Spree–A Magazine of Western New York

Robert Pavlis
Editor of GardenMyths.com
I live in southern Ontario, Canada, zone 5 and have been gardening a long time. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

I hope you find Garden Myths an educational site that helps you understand your garden better.

16 Responses to 'Should Trees be Wrapped in Winter?'

  1. Patricia Lowe says:

    Thanks for all your information. very helpful to me.

  2. Dave says:

    I’ve been told that my incentive to wrap is the prevention of burn. The sun heats the needles on my Alberta spruce and the shrub therefore calls on the root ball to send some moisture North to put out the fire. Problem is the root ball is still frozen, and the needles therefore burn/brown.
    Does that add up? If so, will wrapping help? Will I have to do it every year? I was told I had purchased a spruce from the proper zone, but last year’s burn tells me otherwise. Is it just because it’s a newly planted shrub?
    Thanks in advance for any advice.

    • Browning on evergreens is mostly do to wind burn which is removing moisture from leaves faster than it can be replaced from the roots. Newly plants shrubs have poor root systems and are more susceptible.

      Wrapping in year 1 might help a bit, but should not be needed in future years.

      • Dave says:

        Thanks for the quick reply Robert. I hadn’t given any thought to wind bring the culprit. That’s an interesting angle.
        The reason I found the sun explanation compelling was that I noticed that the burned area on trees around here (mostly Cedars) is almost exclusively South facing… Which is where you will find the winter Sun in my area. I’m a bit North of Sudbury. My two little spruce trees were burned on the South facing, despite predominately NW winds here.
        In any case I’m relieved to hear that as the roots develop I should be able to look forward to decreased maintenance.
        Cheers!

  3. johnh1955 says:

    Covering plants will protect them from frost if the ground temps are above freezing. This is why people cover certain plants in places like phoenix Arizona and Florida when short duration cold snaps hit. Other than that I would never think of wrapping trees that are growing in areas that have real winters every year. Plants don’t generate heat so wrapping them very far off the ground seems like a waste of time unless you first wrap them in Christmas lights. :o)

  4. Hi, Robert, I’ve read that burlap on evergreens over winter can actually capture salt spray and intensify salt damage. Judging by some of the winter-covered junipers on city streets near me, this appears to be true. The sides facing traffic show salt burn in spring, despite being covered. I think in general that people go a little overboard with the burlap, and don’t recognize that they’re doing more harm than good.

  5. Robert, I share your philosophy, I want gardening to be fun and a learning experience. The learning is energy well spent, I don’t waste energy on work that can be avoided.I see those type of chores as “make work projects”.

  6. Jonathan Costa says:

    All the advice is great!!!! I have actually pushed the boundaries of my zone which is 6a or 6b southern Cambridge, Ontario Canada. I have now been successful for 5 years growing a Mexican Fan Palm….. Yup a Mexican Fan Palm in Ontario. I use heat cable, burlap, and bubble wrap, plus a home made shelter, If you wanna see it. Check out my Facebook page. It’s under Jonathan Costa, it’s my cover photo. With proper winterization methods anything is possible. Cheers

  7. Hi Robert
    I live im Manitoba and I have 2 Brandon Cedars that got a pretty bad winter burn last year. This winter my boyfriend decided to wrap them. I’m a little nervous because he used a poly tarp that’s pitch black so there’s absolutely no light coming through. Neither one of us is a experienced gardener so I was just wondering what you would think about that?

    • Black plastic will not keep the plant warm – no plastic will. It might heat up inside the plastic on sunny days and then get just as cold at night as the air temperature. Such extremes are not good for plants.

      Evergreen use light all winter and they do keep photosynthesizing. However, the evergreen branches that spend the winter under snow don’t get much light either and they are OK in spring.

      In short the black plastic will probably not do too much hard, but it is not doing much good either except that it will keep wind from drying out the plant. Now that it is on, keep it on, but take it off very early in spring or late winter, once the worst of the cold is gone.

  8. Fred Koyama says:

    I have been wrapping a evergreen shrubs for long long time because when I look at the evergreen (needles ) in the Spring, The ones that I wrapped up with Burlap got more shine to the leaves ( needles ).

    But I think most impotant thing is Before cold weather come, Give them lots of water water water. Specialy the year that don’t have much rain in the Fall.

  9. Ann says:

    All valid points, though sometimes the struggle is worth it for the plant you want to keep. I grow bananas in zone 5. I get a unique plant in my yard that looks great and is also a great conversation piece.

    • Based on what I have read, you probably do more than just wrap in burlap which I don’t think will keep a banana alive in zone 5. Most people would, remove the leaves which won’t over winter, and then make a circle of wire and then fill that with leaves. The leaves help trap the warmth from the ground around the crown of the plant.

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