Yes, the roots are hardy here, but the foliage gets zapped. If I have the time/space, I take cuttings before frost takes them, to get more roots going over winter. If not given prime light-space, this plant can fade & get gangly over winter, but not to worry, it will pop back to life & purple color once outside again.
Some pics from this morning...
This is the same spot I showed 4/27 (2nd pic) & on May 14th (also 2nd pic.)
This spot was pictured 4/7 & 4/27.
