For many valuable crops, winter protection is essential. But protecting crops too early can interfere with the plant's natural ability to adjust for winter or "harden off." The first step to take for winter protection is to wait, so that plants are given enough time to properly harden off.
Don't apply mulch too early, and don't apply nitrogen (N) late in the season. Too much available N, whether from fertilizers or manure, keeps plants succulent in the autumn and increases susceptibility to winter injury.
Mulching plants is a means of stabilizing soil against freezing and thawing. A thick layer of weed-free organic residue-like straw is best, straw has hollow stems so is a very good insulator.
Leaves also can be used, but if they mat down their insulating value is diminished. Mulch should be applied in late November, after a hard frost or two.
When mulching roses, cut the canes back to fortyfive centimetres, surround with chicken wire and cover the whole plant to protect shoots as well as roots. Low-growing perennial flowers strawberries and the like are easy enough to cover completely, but they may require re-covering if the winds blow off the mulch.
For vines that are not very hardy, remove the vines from the trellis and lay them on the ground before mulching. For upright plants that cannot be lowered to the ground, erecting a fence of some kind can protect plants against drying winds. Sacking or other material stretched between posts works well. So does snow fence. It breaks the wind somewhat even when there's no snow, and works really well to protect plants when there is snow.
Garden planters can be a mixed blessing when you are faced with bad weather. On the one hand the planters are good because you can move them to protect your plants from damage. On the other hand, you may have to move them to protect them from damage.