Trees,shrubs and other plants may be insulated against the cold using hessian, double thicknesses of newspaper or old carpet. This protects them against cold winds, yet allows any warm air escaping from the soil to become trapped under the cover. This insulation also helps to keep the plant dormant throughout the whole of the winter, preventing any early production of buds caused by a mid-winter mild spell.

Some insulating ideas include:

• Create a wire cage around shrubs or small trees. Tie in the branches and then pack the cage with bracken. Cover the top with straw and then secure and keep dry by attaching a sheet of plastic to the netting.
• Build an insulation blanket using a thick layer of straw packed between two layers of wire netting. Bend the blanket around vulnerable plants, filling any gaps between the blanket and the plant with straw. Tie the edges of the insulating blanket together down the sides and along the top.
• Tie up the branches of conifer trees or shrubs and then wrap with strips of hessian. Wind the hessian around the plant, securing it at intervals with twine. Pack straw or bracken around the base of the trunk. This will protect the conifer from harmful drying winds and will also prevent snow from splaying the branches and spoiling the shape of the tree.
• Insulate small shrubs by packing straw around the branches and then securing with a sheet of hessian and twine.
• Protect wall-trained trees and shrubs by covering them with a woven nylon netting. This may be rolled down from a fixed position above the plant in the same way as a blind. However, you must place some canes or stakes at an angle against the wall to prevent the netting from resting on the plant.
• Detach climbing or wall-trained plants from their support and gather their stems together. Pack bracken or straw behind the branches and then cover with a layer of netting secured at the top and bottom of the fence or wall. Fill the area between the plant and the netting with more straw until completely covered.
• Perennial plants that die down to a resting crown may be protected from the cold by covering the crown with a layer of mulch or leaves topped off with layer of evergreen prunings or bracken. Woody plants such as roses may be covered with a mound of earth, heaped up around the crown to a depth of 12 cm (5 in).