My varieties include black adder and sangria that survived the winter. I have Blue Boa, raspberry summer. and a couple of others too. I'm taking basal cuttings of all of them to,overwinter in the GH.
Its the wet that agastaches don't like down here so I guess I could treat them by covering with raised sheet of glass. They are bit tender so cold will kill them too. Its third year for me with black adder and sangria but others are new so very much a learning curve. However, from young small plants they are, most of them, in full flower. black adder, for example, is 4 or 5 feet tall. Blue boa is 3'. Eye catching, erect and long flowering. Will post pictures in couple of weeks so forum can judge them