tropaeolum
Peter Taggart (Sat, 05 Apr 2014 14:44:01 PDT)

In my experience the hardiness of Tropaeoleum tuberosum depends very much
on its planting. It likes to grow shallow in very well drained humus and
behaves very much like a potatoe. I wonder if Tom really has the form Ken
Astlet which should flower much earlier in Summer than the type. Stocks in
commerce in Britain are usually wrongly named. It is certainly hardy to
minus 15 C in the right position and not below 0C in the wrong position.
The Welsh hills tend to be very wet and can be cold too. Parts of the Welsh
coast however are quite dry and almost frost free

Peter (UK)

I did not find T. tuberosum 'Ken Aslet' hardy