Many gardeners grow plants that are not completely hardy out of doors. Tender plants that are left outside will need protection in order to survive. This may involve cutting them back and covering them thickly.
Materials
such as fleece, hessian, straw and polystyrene can be used
to insulate plants from cold or wind. To prevent sweating
and possible rotting, protective covers should be removed
when extended very mild periods are forecast but replaced
when cold weather is again on its way. With a little imagination
insulated plants can make a decorative feature in a winter
garden.
As winter wet can be damaging, grow tender plants in a well-drained soil in a sheltered site. Feed and water plants generously during the growing season to build up strength and food reserves. Feeding in early autumn with a high potash fertiliser or sulphate of potash can help build up cold resistance, as can watering on a feed based on seaweed.
Tree ferns
Grow in moist, shady and sheltered positions. As hardiness increases with height, young plants are more vulnerable to cold damage and should be overwintered in a cool, frost-free greenhouse or conservatory. In dry conditions the trunk may need watering, but avoid getting water in the crown. In mild winters larger plants may survive out of doors with little protection. Insulation should be applied in late October and removed after last frosts. As a minimum pack the crown with straw and keep rain out with a cap of polystyrene. In colder winters wrap the trunk with fleece and mulch the roots.
Bananas
Grow outdoors in a well-drained soil, preferably enriched with organic matter. Shelter from wind is essential to prevent leaves being shredded. Cold, sunscorch and hail also damage foliage. Musa basjoo is one of the hardiest to grow, and Ensete plants grown from seed make striking large plants in less than two years. Small plants can be overwintered in a frost-free greenhouse or conservatory. Cages made from chicken wire can be built around larger plants - after cutting back the frosted leaves - and packed with straw or bracken, covered with hessian or fleece to keep out wind. A hood of polystyrene can help keep rain out of the crown. Unwrap plants by May.
 |
 |
 |
| 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. | Here, the gardeners are removing completely a stem growing too close to the path. | 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. |
 |
 |
 |
| 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. | A second tier of chicken wire is added, so that the stumps are completely encircled. | Straw is piled into the chicken wire frame, pressing it down between the stumps with a small rake. |
 |
 |
 |
| This is continued until the stumps are completely packed with straw. | 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. | This structure should keep your plants secure for the cold season, ready to be unpacked and brought back into active growth in the spring. |
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.
Cannas
Cannas are lifted after the foliage has been blackened by frost. Remove dead leaves and loose soil and store in trays of sand, coir or vermiculite, with the crown just showing. Keep just moist in a cold, frost-free greenhouse or conservatory. Container-grown plants can be stored in their pots.
Plants can be risked outdoors in well-drained soils in the mildest regions by protecting the crown with a thick layer of dry winter mulch such as bark.