Winter Care of Evergreen Hedges

Winter is a difficult time in the garden, especially if you live in colder regions, although even in warmer areas sudden cold snaps can wreak havoc, as happened in the South recently. Snow, cold winds, and in warmer areas periods of dryness, can all damage hedges and destroy the careful work and nurturing of years. So taking preventative steps is always a worthwhile investment of time, and with just a little effort and attention we can make the difference between a hedge that comes through winter looking perfect, and one that needs lots of attention and time to come back again.

Tips for Winter Care of Hedges and Evergreens

  • Keep the soil moist, by watering through fall, and during winter dry spells
  • Protect the foliage, especially with new hedges, by using an anti-desiccant spray
  • Keep salt at bay, with screening placed away from the hedge, not right on it
  • Use a high-potash fertilizer, this element protects from dryness by thickening the cell walls

Water Your Hedge in Winter

In every region, watering is the single best thing you can do for your hedge. In cold areas, where the ground freezes for periods of time, and even all winter long, evergreen plants find it difficult to draw up water from the frozen ground – imagine drinking a glass of frozen water. This means that the foliage, which is still losing water to the atmosphere, especially when dry or cold winds blow, can desiccate and become dried out. This may not be noticeable until spring, when new growth should begin, and instead the warmer days complete the drying process of these already-dead branches. This effect, called ‘winter burn’, is seen not only on hedges but on other evergreens as well, so while watering your hedge, water your specimen evergreens too.

Watering helps because if the ground is very moist it takes more cold input to freeze it, and some un-frozen water will remain available to your trees. Since the foliage will survive best if it is fully plumped-up with water when the ground freezes, you should begin this winter watering in late fall, and continue until the ground freezes. Especially with younger, newer hedges and evergreens, mulch over the soil will also help, not just to conserve the moisture you have added, but to keep the soil warmer and reduce the intensity of freezing.

In warmer areas watering issues can also arise, as long dry stretches are common in winter, and just because the temperatures are lower doesn’t mean the ground is not drying out. It is easy to be caught unawares when cold sunny days draw lots of moisture from evergreen foliage, and directly from the ground. Check around the base of your hedges and evergreens weekly, and if the soil seems dry, give it all a good soaking.

Speaking of soaking, it is also important to water correctly. Standing for a few minutes with a hose spraying is unlikely to be very effective, since you want the water to penetrate deeply into the soil, not just dampen the surface. A slow-running hose pipe, or a soaker hose of some type, will be far more effective in re-filling the deeper water reservoirs in your soil. When putting in a hedge it makes lots of sense to install a simple watering system at the same time, which can even be connected to a timer. You don’t need a full-scale irrigation system – just a trickle hose or ‘leaky pipe’

In colder areas you probably won’t need to water during winter, but watch out when early spring arrives, as then too the soil can dry rapidly as the temperatures rise, especially if it has been a dry winter. Remember to keep checking until your full spring and summer schedule becomes established.

Use Anti-Desiccant Sprays

It is surprising that these sprays, used by professionals for decades, are not used much more by gardeners. Perhaps it is the distrust of spraying, but in fact these materials are all-natural, and so they are completely safe to use. They contain an ingredient called ‘pinene’, which is extracted from pine trees cut for lumber. When mixed with water this material forms a giant network of molecules that becomes a water-proof film across the foliage it is sprayed on. It is this coating that greatly reduces water loss from the foliage, and that makes it so useful. On evergreens in winter, especially if you have planted them recently, it can make an enormous difference, keeping them green and healthy even in difficult and exposed locations. Spray shortly before the ground freezes, and if there are periods above freezing during the winter, especially if it rains, then try to get out and re-spray, as heavy rain will weaken or remove the coating. It is basically invisible once applied, so it is much more attractive, and more effective too, than the old-fashioned burlap wrapping still seen in some colder areas.

Protect your plants from salt spray and runoff

Salt is the enemy of plants. It sucks moisture out of the foliage, and out of the roots too if it enters the soil. Luckily its use is declining, and there are better alternatives for your driveway, especially if you have a hedge alongside it. You can’t control what your city puts down though, so if you have hedges along the roadside, you can easily have them severely damaged by salt drift blown up by traffic or high winds. The best protection is to catch it before it lands on your plants, and the simplest method is to put up a burlap screen, placed a foot or so in front of the hedge, and a little taller. This will trap the salty spray and hold it away from the foliage. A common mistake is to hang the burlap right on the hedge, but if you think about it for a moment, by doing that you are holding a wet, salty cloth against the leaves, which is at least as damaging as doing nothing at all. That gap is important, so make sure you create it when putting up your screening.

Use High-potash Fertilizer in Fall

You won’t see it labelled with that name, but if you read the label you will see a relatively high number at the end of that formula of three numbers showing the composition. These fertilizers are often sold as ‘fall-fertilizer’ for evergreens, and their secret ingredient is the element potassium, often called potash. This is held in the plant sap and causes the cells to take up extra water. Not only does this protect against drying out, it stimulates the cell walls to thicken, so that water is lost more slowly through them. As well, the extra elements in the sap makes it less likely to freeze. Together, all these effects reduce the risk of winter damage to the foliage. Although not really a winter tip, as it should have been done already, it is something to think about for next fall, to give your evergreens the protection they need.