Win the cold war

Guy Barter, chief horticultural adviser at the RHS, says: "Plants differ in their ability to frost-proof themselves and a hard winter might involve prolonged freezes, with pots and the top 20cm of the soil freezing solid."

Plants at risk include dahlias, fuchsias, gladioli, pelargoniums, canna, citrus and olives, although most keen gardeners will have long since lifted summer-flowering bulbs for storage through the winter and brought their tender specimens under cover or indoors during the dormant period.

Mr Barter says: "Roots are often more vulnerable than upper parts of plants, so preventing pots from freezing is sensible and mulching the roots of vulnerable plants such as hardy fuchsias is wise. Tender plants are less able to reduce the prospects of freezing damage and their cell membranes and structures are especially likely to function poorly at cool temperatures. In a hard winter gardeners can expect heavy losses unless they can give protection to their plants. Cold winds remove moisture from evergreen foliage that cannot be replenished from the frozen soil, so leaves and needles are scorched and killed. Hard winters leave many disfigured evergreens and conifers."

The RHS offers the following tips to minimise damage during a really hard winter:

Place a plastic ball to float in ponds to help prevent ice forming and to ease making an air hole for fish to receive oxygen.

Top up stocks of fuel for greenhouse heaters and insulate greenhouses and frames with bubble polythene. Further protection can be given by laying fleece over plants in greenhouses or frames and covering frames with old carpets at night or during severe cold snaps.

Move tender plants in pots to a sheltered place. Greenhouses and conservatories are ideal, especially if they can be kept frost-free. Otherwise wrap the pots in bubble wrap or bin liners filled with straw, cardboard or leaves, and place the pots against a sheltered wall or an open-fronted shed. Garages and other buildings are often too dark, but can be successful with care and luck.

Go easy on watering containers – plants with dryish roots are better placed to resist cold than ones in soggy compost.

Mulch the root zone of evergreens, conifers, tender shrubs and tender perennials with coarse organic matter to help exclude frost and prevent the ground being frozen.

Keep a long pole handy to shake snow off hedges and trees to prevent the snow's weight causing breakages.

Avoid pruning in freezing weather.

Bonfires can be fun, but do be considerate to your neighbours and don't break local bylaws.

Wrap tender foliage in fleece. Be aware that fleece only gives a degree or two of protection so consider straw packing inside the fleece to limit frost

damage.

Drain watering equipment, sprayers and external plumbing.

Don't allow liquid fertilisers and pesticides to freeze as this often ruins them.

Avoid letting lifted dahlias, cannas, gladioli, stored vegetables and fruits freeze.

Keep a stock of parsnips, leeks and other vegetables in a frost-proof place in case frozen soil prevents harvesting.

If you have digging to do, cover the area to be dug with cardboard, old curtains or old carpet to keep it workable.

On a positive note, frozen ground can be helpful if you need to barrow materials such as compost around the garden – just avoid treading on frozen grass as your footmarks will be visible for weeks.

YP MAG 18/12/10