BORDERLINE HARDY SALVIAS

These are plants which I have found  will tolerate temperatures down to about -3. with a layer of mulch applied and planted in free draining soil.

I know that the RHS probably woudn't agree so this I must caveat that this is my experience but I have been growing these plants for many years and certainly in much of southern Britain and in the larger cities you should be fine. And you can always take a cutting......!