The following is a pictorial step-by-step guide to wrapping a banana, as undertaken by the gardeners at RHS Wisley. The principle is the same for any free-standing shrub or tree. If you do not have the exact materials, you could substitute dried bracken fronds or similar for straw, old bits of timber for bamboo canes, another kind of mesh wire for chicken wire, and another suitable waterproof covering (perhaps an old tarpaulin) for the polythene sheeting.
Step 1: The top growth is sawn off, leaving only stumps. Make sure to remove leaf debris from around the stumps, as it could rot under the protective cover, and spread disease to the crown of the plant.
Step 2: Here, the gardeners are removing completely a stem growing too close to the path.
Step 3: Bamboo canes or stakes are driven into the ground in a circle around the stumps, and chicken wire is stretched around the canes to make a frame.
Step 4: The canes are tied to the chicken wire with string or tying wire. Pegs can also be used to secure the chicken wire to the ground.
Step 5: A second tier of chicken wire is added, so that the stumps are completely encircled.
Step 6: Straw is piled into the chicken wire frame, pressing it down between the stumps with a small rake.
Step 7: This is continued until the stumps are completely packed with straw.
Step 8: The top of the structure is covered with thick polythene sheeting, and a ‘lid’ is cut to size and tied to secure the corners. String is used to tie the lid on to the wire framework below.
Step 9: This structure should keep your plants secure for the cold season, ready to be unpacked and brought back into active growth in the spring.