If they are grown in containers, all bulbs that might be described as summer exotics will need frost free conditions at a minimum temperature of 7 degree Celsius to survive in the winter.
Take action before the first frosts are threatened in the autumn.
You must allow the plants to dry off naturally.
Then carefully clean away the soil from corms, tubers, rhizomes and bulbs before storing them in cool, dry conditions.
If you do not have a free frost green house, a frost free garage or shed will be appropriate or even somewhere indoors, as long as it is not too warm.
It is important that the bulbs do not start into growth too early.
Replant the bulbs in fresh compost in spring.
Alternatively, the plants can be left in their container and the whole pot or basket moved into a frost free green house.
Here, they will remain dormant through the darker, cold days of winter and burst into life when the longer, warmer days return in spring.
When temperatures fall close to or below freezing, heat the green house with a thermostatically controlled electric heater which will turn on automatically at a pre set temperature.
If you do not have electricity in your green house, use a paraffin heater, re-lit every day as necessary.
When temperature rise above freezing in the daytime, open the greenhouse door to allow air to circulate and remove any build up of moisture.
Although pots can be moved outside in late spring, during the daytime, cold evening temperatures mean that they are best brought back into the shelter of the greenhouse.
Only leave containers outside all day and all night once all risk of frost has gone.