Cold shoulder

At the time of writing, frosts have been rather thin on the ground this winter, in every sense. So perhaps an ode to master jack will entice this most useful of tools into our gardens before Spring.

Apart from mild weather just not feeling right at this time of year, a period of cold frosty weather provides an invaluable service to the gardener, from the mechanical, to the biological to the aesthetic. Hardy plants are also unaffected by temperatures down to –15 degrees Celsius so come the spring should romp away unharmed by a frigid winter.

Farmers have, of course, always known how to make the most of frost as an agent to break down heavy soil into a good tilth, and the same principal can be applied to the garden. Working a heavy soil by hand is back breaking, but the trick is to use your spade or fork to start the process in autumn by simply breaking the soil up into large clods and then letting the frost do the hard work over winter. By spring the clods will crumble away and organic matter can be worked in with relative ease.

Frosts are also invaluable as a way of breaking the breeding cycle of many garden pests and thereby significantly reducing their numbers by Spring. An extreme example of what can happen if this cycle goes unchecked is being played out as we speak in the USA where pine beetles, no longer subjected to long, and extremely, cold winters, are decimating vast tracks of forest. Closer to home, and on a more domestic scale, it will probably mean a mini plague of aphids and slugs. 

Many plants have also evolved to respond to a period of cold weather. The transitions from autumn to winter and back to Spring, provide the trigger to enter into and emerge from hibernation. For some, a sustained period of low temperatures is actually beneficial, thus the ability to trick hyacinths into flowering early by artificially chilling them and the reason why the apple harvest was so bountiful in 2011.

From a purely aesthetic point of view, a crisp frosty winter is always preferable, in my mind, to the relentless drabness of a mild one. Having said that I feel that in the interests of balance some mention of the downside should be made. Many popular garden plants, such as Hebes, Fuchsias and Penstemons, are at best borderline hardy and will sometimes struggle to survive prolonged periods below –5 degrees Celsius, particularly if other factors contrive against them such as damp and wind.

Freezing can also cause considerable ground movement which can cause the roots of young plants to be damaged by being lifted, while frost pockets, where cold air collects at the bottom of slopes, can create very challenging conditions. And of course no one likes a late frost! Given the choice though I would prefer the cold comfort of a chilly winter everytime.