Now you’ve got all those marvelous tropical plants in the garden and some of them are a little less hardy than others.
How do you protect the less hardy plants from frost?
Gather all the pots in a sunny and sheltered spot and cover them with veil of winter fleece or burlap.
You can also place the pots on a polystyrene panel to isolate them from a cold, wet soil.
Bring the potted plants in an unheated room. The majority will not like the dry air of a heated room but will tolerate a room with a temperature of minimum 10-15 °C.
Place a thick mulch layer of leaves or straw at the base of the plant or on top of the roots (at least 30 cm).
To prevent mulch to be scattered by the wind, throw a few shovels of dirt on top or span a winter fleece, burlap or net over the mulch layer and fix it in the soil.
The plant can be packed in a material that allows light and air to pass, such as winter fleece or burlap.
It is important that the material allows light through to prevent the plant to die.
It is also important to have air flow to prevent the plant from rotting.
Do not use plastic sheet, unless it has openings for air circulation.
Do not use bed covers: they let little or no light through and tend to withhold moisture, unless the cover is extremely worn.
The packing can be removed on dry sunny days to aerate the plant.
Wintering fleece can be found in the trade as sheets or as ready to use sleeves, even with a zipper.
Build a wooden frame around the plant and wrap with plastic sheet.
This cold frame can be heated with outdoor lighting. The lamps emit heat so that the temperature is slightly higher than outside the cold frame. For safety, use only lighting designed especially for outdoors because this is protected against moisture.
Plant a few wooden posts around the plant and build a sleeve with a piece of chicken wire or fence wire. Fill the void with straw or leaves.
The sleeve may be surrounded with a winter veil, burlap or a bamboo fence.
What does and doesn’t a wintering veil or burlap do:
A wintering veil or burlap prevents wind to have free rein and protects the plant against the cooling and drying effect of wind.
The meteorological temperature is measured in a shaded area and out of the wind. In a sunny spot, protected from the wind, the temperature will be warmer but in a place exposed to the wind, the temperature is colder than the meteorological temperature.
As the fabric protects the plant against the cooling effect of the wind, the temperature will be slightly higher within the protection relative to the temperature under the effect of wind, but equal to the meteorological temperature relatively quickly.
Winter protection for bananas:
Regardless of a given hardiness, the aerial part of a banana plant (leaves and stem) dies at 0 °C.
The difference in hardiness comes from the cold resistance of the tuber, corm or rhizome.
There are two ways to protect a banana tree in the ground against the cold:
- Mulch: cut the plant at ground level and cover with a thick mulch layer of straw or leaves. The plant will restart from the foot next spring.
- Packing, cold frame or sleeve: cut the leaves to the pseudostem. Now wrap the pseudostem. If the winter is not too cold and wet, the plant will restart the trunk spring. If the pseudostem dies anyway, the plant will restart from the foot.
Snow has a high insulating power. It is not necessary to rid plants of snow, on the contrary.
Plant hardiness is not an exact science. Temperatures are measured for a species in a specific location, but may vary depending on conditions.
The hardiness of a plant also depends on exposure (sun, partial shade), its exposure to wind and draining power of the soil.
In general, well-drained soil increases hardiness.