On Thu, 12 Aug 2010 22:51:19 +0100, "Bob Hobden"
wrote:

This tropical plant is sometimes said to be an annual in the UK yet others
say it is a herbaceous perennial. So which is it, and has anyone grown it
and overwintered it successfully outside or does it have to be taken into a
frost free greenhouse.

I have grown it, but only as an annual. I'm told that it forms a
tuber like a dahlia but I've never managed to overwinter one. A
neighbour who used to grow it had it reappear one year in a very
sheltered position.

Pam in Bristol