Last winter many gardeners were caught out as a result of the sub-zero temperatures and sustained periods of frost and snow. The increasingly mild winters before 2008-09 meant that we had been lulled into a false sense of security, leaving tender and exotic plants unprotected in the garden as if they were simply holidaying in their native Med, South Africa or sub-tropical rainforests. In recent years many people had bought specimens such as palms, agaves, bananas, tree ferns, oleanders, olives and cannas for their architectural value. But for some this turned out to be an expensive mistake as pot loads of plants were killed off, and others were heavily knocked back and have been slow to recover.

As night temperatures start to plummet, it’s time to do what you can to ensure that you can get these specimens through the winter safe and sound. If a plant is grown in a pot and can be moved by lifting (bend your knees!) or wheeling around on a sack trolley, move it into a frost-free conservatory or greenhouse if you have one. The conservatory should not be centrally heated as the warm dry air and change in temperature will probably end up doing more damage than good.

If you don’t have a greenhouse or conservatory, put these plants together in the most protected spot in your garden. This could be down a side alley, in a basement well, in the corner of the garden where two walls meet or even under a large, preferably evergreen, tree. The air will be marginally warmer here and they will be protected from cold winds and less prone to ground frosts. Consider buying or making a temporary greenhouse/polytunnel structure out of bent plastic pipes; or a wooden frame clad with plastic sheeting or bubblewrap; or even a lean-to tent affair against a wall. If you use plastic, make sure plenty of air can circulate around each plant. Most of these types of plants hate the wet more than anything and will cope with colder temperatures if they are dry — especially plants from arid conditions such as agaves, yuccas and echeverias.

If your tender plants are grown directly in the ground, you will need to do whatever you can in situ. Unfortunately, whatever you do do will be rather unsightly as you will probably end up creating strange ghost-like figures in your garden. In milder areas wrap plants with winter fleece or ready-made fleece bags or jackets; be sure to secure them with string or wire as they can easily be blown off. Old hessian sacking works well for larger, stouter plants like tree ferns, but make sure they can breathe.

In colder areas construct a simple framework around the plant using chicken wire and stuff it with plenty of dry straw for insulation. This works particularly well with palms, tree ferns and bananas — the latter will develop a tall trunk rather than dying back into the ground like a regular herbaceous perennial. Remember, the older a plant gets, the tougher it will become and the more cold it can withstand.

The cabbage palm, Cordyline australis, is a pretty tough character, but may benefit from having its leaves tied into a bunch above its head like a disco diva. This will keep the worst of the frosts and wet out of the most vulnerable area, the crown, from where new growth appears in spring.

Don’t use plastic or bubblewrap directly around plants as it will simply hold moisture in, make them sweat and considerably increase their chances of rotting off.

Cannas and gingers are a different story as they die down into the ground. These are a bit trickier as the advice varies depending on where you live. In milder areas you can leave them in the ground, cut them back to 6in above ground level as soon as the foliage blackens in the frost and mulch thickly with at least 4in of organic matter. Plants left in the ground may not flower so well next year as they come into leaf late and have a shorter time to bloom, but it’s far less hassle than digging them up to overwinter.

If you live in a cold area you have no choice: cut the foliage off, put the rootball into a plastic bag with a few holes in it or large pot, and put it into a frost-free garage or greenhouse and make sure it doesn’t dry out. It will sit there dormant but should be fine for planting out the following spring; with luck, it should come into flower in the late summer.

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