Protecting Plants from Frost and Snow
You can avoid the major effects of frost damage by planting fully-hardy plants, avoiding frost pockets and by using sunny, sheltered positions for more vulnerable species.
A thick layer of organic mulch, such as compost, can provide insulation for plants roots over the winter, and if you allow herbaceous plants to die down naturally at the end of the season, their foliage and stems will protect their crowns.
There are a number of other methods for protecting plants over the winter; trees and shrubs may be insulated with layers of hessian or straw, roses may be trenched, and cloches and polytunnels used to protect individual plants.