Shurly some one must have experiance of Black Boy

[PaddyS]

Hi All,
I have Xanthorrhoea, black boy or tree grass, a preserved species which was
abandoned by previous owner.
I suspect it has spent the whole of winter in the outside, in the UK. I know
it is slightly tolerant of frost but the twits left it out all winter, and
the grass head is brown, and the grasses are beginning to shed.
Has anyone else had experience of this plant, it is Australian in origin.
There must be an Aussi out there that can advise.
Paddy