Tropaeolum pentaphyllum
Brian Whyer (Mon, 20 Oct 2008 10:53:43 PDT)

I have had this plant outside in a large pot against a south facing wall, and now heavily screened behind culinary bay and sage bushes etc. It grows up most years to a height of 8 feet into a clematis armandii before getting frosted sometime in the winter; and usually before flowering. I guess I may have had serious flowering for around 3 years out of the last 15 or more.
This is in a garden where I have had pots of Tropaeolum tricolor flowering in unheated glass and plastic greenhouses. They look a bit sad when frosted but recover as the temp. rises, and when I tire of them in mid April take late spring frosts in full flower in the open, before going dormant.

Brian Whyer, Buckinghamshire, England

--- On Mon, 20/10/08, John Grimshaw <j.grimshaw@virgin.net> wrote:

Uli Urban wrote about Tropaeolum pentaphyllum:

I have never tested with my plants but I
think it is not very hardy and is not suitable for outdoor cultivation
in winter cold climates below freezing.

This has always been my view as well, but earlier in the summer I was
visiting a garden in the Cotswolds and saw the familiar flowers of T.
pentahyllum twining round something else. I expressed my surprise and was
told it was hardy there! The garden in question is even higher than we are
here, so I shall put my plant out for 'hardiness testing' next spring.
It
certainly doesn't deserve precious greenhouse space...

John Grimshaw

Dr. John M. Grimshaw