In article , says...
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.


Its invasive and I ended up burning all the root I could find but it
still came back for many years on the compost heap, I know several
gardens pre the last winter that had been growing it as an outdoor
perennial, but it was too fast for my liking (bit like those Physalis
things)
--
Charlie Pridham, Gardening in Cornwall
www.roselandhouse.co.uk
Holders of national collections of Clematis viticella cultivars and
Lapageria rosea