Is Your New Hedge Ready for Winter?

So you recently invested in a new hedge – probably Thuja Green Giant, since that is the most popular hedging plant across most of the country. Perhaps you planted it back in the spring, or maybe it was more recent, and you took advantage of some of the price deals around and planted in September. So you are probably looking at your plants right now and feeling a bit concerned that winter is coming. You don’t want to be looking at a row of dead plants when spring rolls round again. Don’t worry, it won’t happen, at least not if you take a few simple steps to give your plants the best chance of surviving. Let’s look at some key things that will make sure spring brings you a perfect row of plants, ready to take off and grow you the perfect hedge.

Trim Your Hedge in Fall

If you planted in spring you perhaps have not trimmed yet. Maybe you are thinking the best thing to do is wait until the plants reach the size you want, and then start trimming. That is definitely not the right thing to do, as trimming should be on your ‘to do’ list right from the beginning. Taking off an inch or two regularly will build a solid, dense structure and give you the best hedge when it does reach its ideal height. It will also make keeping it at that height easier.

As for going into winter, a neatly trimmed hedge will resist wind and snow damage much more successfully than if it is overgrown, with branches shooting in all directions.

So take out your hedge trimmer, and go lightly over the hedge, removing longer shoots and taking the tips off, so that it looks neat. Leave the bottom wider than the top – that is, slope the sides inwards by a few degrees, and take more from the top than the bottom. You want to keep that bottom growing strongly, and narrowing the top is the best way to do that. While a dead straight side profile might appeal to you, that slight lean inwards actually looks very neat, and is the right way to do it. When you are done, don’t forget to clean and sharpen your trimmer before putting it away for the winter.

Fertilize Your Hedge in Fall

Using a fertilizer designed for fall application is always a great idea to set your hedge up for winter. These blends contain less nitrogen, so they don’t cause a big burst of growth, that could be damaged by colder weather. They should contain more potassium than normal. You can check this by looking at the last of the three numbers on the bag that show the analysis of the fertilizer. It should be at least half the first number, which is nitrogen. More than that is fine too.

Potassium makes strong cell walls, and raises the mineral levels in the cells. This acts like anti-freeze, protecting against cold injury, and the thicker walls protect against insects and diseases. Potassium also makes the stems stronger, so they are less likely to be blown over, or bent by the weight of snow. Of course, Thuja Green Giant is not likely at all to be attacked by pests or diseases, but a little protection never hurts.

Water Your Hedge in Fall

Now we come to the most important thing of all – watering. If you live somewhere where the ground freezes in winter, more than an inch or two deep, then your evergreens are at risk of winter injury. This is especially so with newly-planted material, such as that new hedge we are working to protect. Here is the thing – evergreen foliage continues to lose water in winter, even though it is not growing. In fact, because the air is very dry in winter, compared to summer, your plants lose a lot of water, especially when a cold, dry wind is blowing. That water must be replaced from the roots, but if the soil is frozen, then so is the water in it, and those plant roots are trying to suck an ice-cube, and are not getting much water from it. So the foliage dries out, and in spring, as soon as the temperatures rise, it turns brown, which we call ‘winter burn’.

The solution is to make sure that those roots have as much water as possible available to them. That way the foliage is not already dry when the coldest weather arrives. As well, that water in the soil slows down hard freeze, so there is still some ‘free’ water around for the roots to take up. So, water every week or two, from early September until freeze-up – your hedge will love you for it, and you will love the fresh green foliage on your hedge when spring comes.

Mulch Your Hedge in Fall

Covering the soil at the roots is also an excellent job for fall. If your hedge is newly-planted, the you may have done this when you planted it. If there is still a good layer, then you are set to go. If not, then a couple of inches of organic mulch will do the trick. Cover the ground out from the hedge, as the roots may already have begun to spread, but keep the mulch off the stems. Something rich and organic is better than bark, and bark is better than stones, but of course what you use will depend on what is available, and the look you want in your garden. Mulch will conserve water, and it will insulate the ground, reducing freezing, and so protect further from winter burn.

Protect Your Hedge in Fall

One of the last jobs of the season is to give your new hedge some protection, depending on where it is located. If it is along a road or driveway, and salt is used, then there is a risk of salt damage to the foliage. Thuja Green Giant has good tolerance of salt spray, but when young, even that tough plant will benefit from some protection.

There are two ways to go. If the risk of salt damage is fairly low, then an anti-desiccant spray will do the trick. These sprays put an invisible plastic coating over the foliage, keeping salty water away, as well as protecting against winter burn by reducing evaporation from the foliage. The second choice is the traditional burlap screen. This is a roll of burlap attached to poles and strung in-between the source of the salt and the hedge. Make sure it is taller than your hedge, and keep it at least 6 inches away from the foliage. Some people make the mistake of putting it right on the hedge, but if it becomes soaked with salty spray, then you are going to make the problem worse, not better.


If you do these simple things, your beautiful new hedge is going to look just as beautiful in spring, and you can look forward to years of beauty from it – especially if you made the wise choice of Thuja Green Giant.