Opinion Likes ?

This plant only blooms on the previous year's stalks, so while it can be grown as an herbaceous perennial at the upper limits of it's zone hardiness, it is unlikely to flower if it dies down in the winter.

I have grown this in zone 8 for a number of years, and have even enjoyed seeing it bloom after milder winters during which wrapping it with frost cloths was sufficient to keep it from sustaining frost/freeze damage - but in harsher winters, even with a good wrapping of frost cloths, it died back, but failed to bloom on that year's regrowth.