Temperatures where I live in Derbyshire, England, rarely get below 10 F but two years ago there were nightly temperatures of around 0 F, the winter before was around 5 F, in each case for a period of several weeks. These are the temperatures I am stating as the limits of hardyness for these plants, in the forms I grow. Other species such as T laxa, B terrestris, T peduncularis all survived these temperatures. These periods were largely without snow cover. I do not grow the same range of material as Jane and others as they are rarely available. Peter (UK) On Sun, Nov 11, 2012 at 1:31 AM, Gene Mirro <email@example.com> wrote: > "what are your minimum winter temperatures in SW washington? > Peter (UK)" > > I've been at this place since 2007, and I believe the lowest temp was 12F > (-11C).