Will tolerate light frost for a short period (say a night or two) and even then the foliage will be damaged.

As Bamboo says, it will be cut to the ground by anything much colder than freezing point.

However I do know of one Cornish gardener who does grown this outdoors, where it basically retreats underground each year and then re-shoots with new growth each spring...although I seem to remember it had never been colder than about
-5C.

Although the plant is usually evergreen the fact that it's able to do this suggests that it once had to survive colder temps than it now faces in the wild.