After such a mild autumn in the UK, the cold snap that greeted the start of winter certainly caught me by surprise. Luckily there was a dry weekend before the hard frosts set in when I was able to move some tender plants under cover and tidy up the vegetable and cut flower beds.

The combination of cold and wet

Compared to other countries on the same latitudes as the UK, we have a relatively mild climate. While temperatures can dip below -5C this is a relatively infrequent occurrence. Being surrounded by sea, the warming influence of the Gulf Stream and a changing climate mean prolonged cold spells are, at the moment, rare. The biggest winter threat to many garden plants is the combination of cold and wet – many plants are hardy enough to tolerate the cold but combine that with sitting in wet soil and that’s when they can perish. The freezing, thawing and refreezing caused by fluctuations in the weather is another problem as milder spells of weather, particularly in late winter, can encourage a plant into early growth only for it to be damaged by a sudden return to cold conditions.

If it does snow heavily it’s important to carefully brush snow off trees and shrubs because the weight of the snow can cause branches to snap.

Some plants that are borderline hardy such as penstemons and gaura have a greater chance of surviving the winter if the top growth from the summer is left in place until spring, as the foliage provides a microclimate around the crown of the plant. They also prefer to be grown in free-draining soil.

Mulching

Mulching is another way to protect the crown and roots of a plant. It’s best to use a dry mulch such as chipped bark, straw, shredded leaves or bracken for winter plant protection rather than compost, which would hold onto moisture and possibly cause the plant to rot. Although chipped bark can be a problem as it’s a way of introducing unwanted honey fungus into the garden. I like to use branches of pine from the Christmas tree. Inevitably I’ll need to prune some branches from the base of the tree so that it can fit into its water reservoir, so I use these to protect vulnerable plants in the borders by simply creating mounds over the plants. Then in spring as it warms up the branches can be removed and composted. After Christmas, when I take the tree outside, I’ll remove all the side branches and use these too.

Other plant protection

Horticultural fleece is a popular way to protect plants – it can be wrapped around plants – but it’s made from plastic and is easily damaged by the weather. Sheep’s wool matting is a great eco-friendly alternative – wrap it around outdoor pots and tie in place with some twine or place over plants as a temporary cover.

Hessian made from jute fibre can also be used to insulate pots, and it can wrapped around a frame of chicken wire positioned around large plants such as bananas. Any gaps between the chicken wire and the plant can then be packed with straw or bracken.

Simply gathering pots together in the lee of a house wall – the warmth given off by the building will raise the temperature by a degree or two – can be sufficient to give most container plants some protection.  

Don’t despair if you don’t see signs of new growth in March as some plants can be slow back into growth. If the winter has been a harsh one it’s well worth waiting until May or even June before you write off a plant.