Plan ahead in case of a third freezing winter
AFTER two very hard winters, and considerable losses of garden plants, it is to be expected that garden owners are nervous about the coming months.
Before the last two exceptionally cold winters, there were 10 mild winters. During the mild decade, the possibility of a very cold winter was rarely raised but it was always a possibility.
So the question is whether winter can now be depended upon to bring a spell of very cold weather?
While it is possible, the chances of a very cold winter are very slim indeed. The chances of two-in-a-row were very small, and a three-in-a-row freezing winter is really unlikely.
That said, it is possible and what do plant lovers do? To protect outdoor plants against cold is possible to a limited degree. It is possible to cover tender shrubs, such as hebe, bottlebrush and fuchsia, with a layer of horticultural fleece or bubble wrap or even old blankets, as long as the latter are taken off after a few days.
But this kind of cover only protects against a few degrees of frost. Prolonged severe frost penetrates such covers and renders them useless. The old-time gardeners used to cover shrubs with cut branches of conifers but this is also of limited value.
Trees and shrubs in the open ground generally have to be left to their own devices, any covering done is hardly worth the trouble. But it is beneficial to knock heavy snowfall off the tops of shrubs and branches of trees as the load can cause shrubs to split open and sometimes to break branches.
Tender plants in pots can be moved under cover and given some protection with a frost protection heater in a greenhouse. Tubers and corms of frost-tender plants, such as dahlias, begonias and gladiolus, can be lifted and brought into a shed or greenhouse, but it is essential to ensure that the shed is frost-free, and a small heater might be necessary to ensure this on the coldest nights.
It is also possible to cover these tender tubers and corms, and other tender plants, such as alstroemeria and lobelia, where they grow in the open ground. Frost rarely penetrates more than 5cm, although it penetrated as much as 15cm last winter.
A mulch of topsoil, bark sand or ashes on top of the soil to give a cover of 15cm, including the existing soil, over these plants should be enough to protect them in a cold winter. This is not a big task or costly and it works quite well. It might be worth considering in the colder inland parts of the country.
And remember it can be done in a hurry, if the forecast is dire!