Although in most areas fall is still in full swing, winter is indeed just around the corner. Some years it comes gradually, and other times it arrives out of nowhere. Which ever it is this year, now is the time to get ready for it. If you live in warm zones, that might mean very little, but in colder areas, where winter damage from cold, ice, snow or salt is common, some preparation now will make all the difference. You can avoid burnt foliage and broken branches with a few simple steps – done in fall.
Winter-proof Your Hedges
- Trim in fall – a tight trim before the cold arrives will protect it from breakage
- Apply fall fertilizers – choose a mix that is blended for fall application
- Water well through the fall – even if rain has fallen, soaking the roots protects against winter burn
- Protect against salt damage – burlap screens take some time and effort to erect, but they do the job better than anything else.
Trim in fall to protect your hedge in winter
The worst thing for a hedge is to go into the rigors of winter needing a hair-cut. An overgrown hedge will collect snow and ice, and branches will be caught by the wind more easily. The weight of that snow, and the twisting of the wind, caused broken branches and collapsed hedges. So get that trimming done well before winter comes, but after the growth has started to slow down. In cold areas that means late September or early October. In warmer areas any time in October is usually going to be suitable. The goal is to leave a few weeks for your hedge to harden after trimming, and perhaps produce a little fresh growth, and if you trim late that new growth will not have ripened enough to prevent it burning.
Hedging plants like Thuja Green Giant are very fast growing – the fastest evergreen around – so even if you trimmed in summer the chances are that there will be significant new growth on your hedge. Get out and give it a trim – you will really see the benefits next spring.
Two things to look out for. First, many people cut hedges by moving the trimmers upwards only, not downwards. This is a mistake, since it encourages long stems growing up the face of the hedge, and these are easily dislodged by wind and snow, leaving big empty spaces. Instead, always trim in all directions, so that the branches are more horizontal, with short ends branching out. This way, not only is the hedge structured in a more stable way, if a branch does die it leaves a smaller hole that fills in more quickly.
The second thing is the top. If you regularly have heavy snow, a rounded top will shed it better than a flat one – which admittedly does look more formal. If you do insist on a flat top, taper the sides in a bit more than normal, so that the top is as narrow as possible. Less snow will build up, and the chances of breakage are greatly reduced.
Put down a fall fertilizer
We usually think of fertilizer as something to put down in spring and summer, to stimulate lots of growth. Usually we don’t want growth in fall, as it will be soft and easily damaged by the cold. But there are other essential nutrients for plants – potassium in this case – which don’t stimulate growth, and instead increase cold resistance, and disease resistance too. Visit your local garden center and look for fertilizers labelled for fall, for evergreens. These have a lot of potassium, and not much nitrogen. Apply them straight after trimming, and they will toughen up your hedge to face the onslaught of winter.
Some of these fall fertilizers go even further. If you see a high nitrogen content on them, this is because the nitrogen is in a form that needs warm temperatures (over 40 degrees) to work. So they sit all winter, and kick in when spring arrives. This means no need to fertilize your hedges until early summer, so that is one job saved from what is a very busy season – a real bonus.
Keep up the water supply
Perhaps the single most important thing to do for your evergreens in fall is water them. This applies not just to hedges, and not just to newly-planted evergreen trees and shrubs, but to all of them, especially ones that you have seen burned in winter before. Often evergreens in foundation planting around the house have problems because the eaves reduce rainfall, and the ground is often dry.
Because these plants still have leaves, they lose water to the air all winter long. Cold winter air is very dry, and so they lose more than in summer. If the soil is dry they may not be able to keep up, and so the foliage dries out. There is a more subtle reason as well. If you live where the ground freezes hard, then plants can’t pull water from it easily – like trying to drink by sucking an ice-cube – but without a warm mouth. The more water in the soil, the less it freezes, and some water tends to stay in liquid form between the soil clumps. By soaking the ground a few times in fall – early on and then just as the ground is starting to freeze up, you make it easier for the plants to take up water, and so avoid winter burn, which is really a desiccation injury.
Protect your hedge from salt
Salt spray from roads and run-off from driveways causes a lot of damage to evergreens. Thuja Green Giant is one evergreen that has pretty good salt resistance, but others are not so good. The best way to protect from run-off is to stop using salt on your driveway. Switch to sand, which gives good traction without damaging your garden.
For highway salt, erect a burlap screen between the hedge and the road, higher than the hedge, to catch what drifts over the top. The secret is to put it a couple of feet in front of the hedge, with a space between, and NOT right on the hedge, as you see done so often in areas with deep winters. That way the burlap catches the salt, and stops it reaching the hedge. Letting the burlap touch of course simply holds the salt right on the foliage – worse than doing nothing at all. Screens also slow down the wind, and they protect from desiccation injury as well.