Question: what plants are frost hardy?
Answer: Coneflower (Echinacea) Though the coneflower does not maintain its beautiful purple coloring in freezing temperatures, it will come back in the spring, strong as ever, if properly cared for in the offseason. ... 
Lily of the Valley. ... 
Blue Spruce. ... 
Wintergreen Boxwood. ... 
Catmint. ... 
Coral Bells (Heuchera) ... 
Pansies. ... 
Hostas.