How to Protect Climbing Plants in Winter
One of the reasons for growing a plant against a wall is to give some extra protection to plants that would be killed or damaged by a winter in the open. Some of these plants may need additional cover in their first few winters, until they become established.
It is difficult to cover completely half-hardy or tender shrubs which have grown to more than five feet (1.5 m) high, unless it is something really very special. The main aim with established plants is to protect the lower parts of the stem and branches up to about 3 feet (90 cm) from the ground, from which new growth can develop in spring if the unprotected parts of the plant are injured or killed by frost.
The time to put on the covering depends on the weather. Severe weather before December or even January is unusual, and the longer that covering is delayed the more acclimatized to low temperatures the plants will become. But, to be on the safe side, the plants should be covered by the end of November. Remove the protection in early March, when the weather has usually started to warm up.
Probably the best and most convenient material to use is dried bracken that has been cut in late autumn. If this is not obtainable short straw is quite effective. Tuck the material lightly in around the lower branches, allowing air to circulate freely through the material so that it remains relatively dry at all times; this is an important factor during frost. A few stakes and some twine will help to keep the material in position. The use of dead stems such as Michaelmas daisies, Solidago and similar material cut from the herbaceous border, can also be effectively used in the same way.
Another method quite often adopted and one which can be used for several successive winters, is to place a thick layer of bracken, straw or other similar material between lengths of small mesh galvanized wire netting or polythene film, which is firmly tied together to keep the material in position. The netting can then be cut into various lengths as required and held in position by a few stakes. Pieces of sacking or coconut matting can be cut into the required lengths and used in a similar way.
With plants of a semi-prostrate habit the material can be lightly worked in and around the stems and if necessary held in position with a few short upright stakes.