Peter Dowdall says despite common thinking, the snow had many benefits to your plants
When we see the snow we tend to think immediately that it’s damaging the garden when, in fact that’s not necessarily the case at all. We don’t always experience snowfall during the winter in this part of the world, so its presence is always something of a conversation starter.
It doesn’t do much in terms of damage except, physically where heavy snow on trees and shrubs can force branches to crack and split and even entire specimens to fall over. The rest of the damage caused at times of snowfall is down to the low temperatures and freezing conditions, rather than the snow itself.
In fact, the snow offers some benefits to the winter garden, acting as a duvet on the surface of the ground. Snow, which is filled with pockets of air will keep the soil warmer than if it were exposed to sub-zero temperatures, insulating the ground and the life beneath, enabling the roots to absorb water and the earthworms and soil microbes to continue to do their thing beneath the surface.
Snow brings naturally-occurring nutrients from the greater environment, as nitrogen and sulphur attach to the snowflakes and are released into the soil as the snow melts. Many plants, such as roses, are said to perform better after a winter which saw some heavy snowfalls and this could be because of the increased levels of nitrogen and sulphur or it could be as a result of the freeze and thaw action on the soil which improves the soil structure.
Many plants can tolerate weeks of sub-zero temperatures and snow covering, provided it’s at the right time of the year. Their situation is important however, when it comes to the thaw. For plants that are facing the first rays of the days, sunshine can burn — thawing the frost too quickly. Therefore, try to position anything which may be at risk beneath the shelter of trees and walls or ideally facing any which way but east.
Plants are nearly programmed to expect low temperatures and snow during the winter and very early spring period, but once the new growth has started, then they become very susceptible to damage. So, a plant which could take a month of snow in December to February and appear unblemished, will suffer the effects of one night’s low temperatures in April or May, as the new growth is too tender to tolerate the cold.
Low temperatures and snowfall are part of the seasonal makeup in these parts and many plants need it to thrive. Spring flowering beauties such as camellias and rhododendrons will start actively coming back into growth after a period of snowfall, nature’s switch announcing the onset of spring and a new season once more after the snow has passed. Bulbs too, like daffodils and crocus need the low temperatures to get the hormones moving in the bulbs and as a result of the recent snowfall here, we should see better blooms on our daffs and tulips this year.
I remember, when studying propagation techniques in college, learning that certain species could be grown from cuttings taken at this time of the year and that for rooting to be successful, these cuttings shouldn’t be taken until after a period of snow or low temperatures, as this was responsible for increasing levels of hormone activity. From memory, mahonias, berberis and junipers all fell into this category and I’m fairly certain too that it also included many other conifer species. Again, the wonder of nature doing her things in ways that we can never begin to fathom.
Sub-zero temperatures will also kill off many more garden pests and solve more problems than they will cause, and the snow will act as insulation. However, when we get an icy wind on top of the extremely low temperatures, then that’s when the damage is caused. Wind with snow causes physical damage, but even for those trees and shrubs that weren’t covered in heavy snow, the recent visit of Storm Emma will have dried out the leaves, stripping trees of moisture.
Many plants will appear blackened over the next few weeks in a similar way to how they looked after Ophelia called. The difference being this time that they may not come back into growth. Those severe winds coupled with the freezing temperatures will have been enough to kill many specimens and so, the next few months will see a substantial change in the landscape of many gardens throughout Ireland. Will all the damaged plants recover? The answer, is no.
Will yours recover, the answer requires that most horticultural of all attributes, patience, as you will have to simply wait and see.
The risk of severe frost or more snow is gone and so any plants that have been covered in horticultural fleece to protect them from the worst of the winter weather can now be unwrapped and allowed to breathe.
Plants growing in pots should be raised off the ground a small bit during the winter to allow excess moisture to drain off.
If the pots are drenched, then when the low temperatures arrive, the roots could freeze in what will become a giant lump of ice.
Again, this is something to remember when the snow is thawing.
As it melts it fills pots and beds with moisture, often welcome as the plants need this to kick into growth however, there’s a fine line between welcome water and too much to make the pots waterlogged.
Lawns will be looking for their first cut immediately now when the temperatures increase.
Set the mower to the highest setting and cut away now but do avoid going on any lawns when they are frozen.