Hello: I'am also in zone
6b and I planted my Stella's three years ago
in June and they are doing great. I did plant "plants" and not bare
roots. I prefere the plants over bare root because I fell they will
establish faster, If planting bare root it should be done in earlyspring
so the plant has a chance to set roots and grow some before
winter sets in. This is from my experence though.