The Cornish Palm (Cordyline australis) may not strictly speaking be a
palm, but is almost universally regarded as one. The last really cold
spell ('87 I think) killed a lot, and even the -4.5C in Jan '97 killed
some off. They are susceptible to being killed by ice crystals, even
at -2 or -3.

Graham

I grew the variegated Cordyline australis in my garden back in Worcester. In
fact, they grew everywhere as the local garden centre was always flogging
them off cheap so everybody bought one thinking how exotic they were. Frosts
down to -8C didn't seem to bother them at all.

I also had a canary palm growing in the front garden and that seemed to
thrive there and not be bothered by the severest of frosts.

It seems to me that some plants can adapt to quite harsh conditions even
though in their native lands they may not ever experience such things.
________________
Nick G
Otter Valley, Devon
83 m amsl
http://www.ottervalley.co.uk