Answer: Perennials are sometimes difficult to overwinter in pots, even if they are winter hardy, because you still need to insulate their roots. Using larger pots such as half barrels, or moving the pots to an unheated garage, or piling mulch around them or sinking the pot in the ground for the winter or even packing it in a styrofoam cooler along with dried leaves or straw are all methods of trying to insulate the roots. I think it's worth a try, though. If the plants do not survive, you can replace them in the spring. But if they do winter over successfully you can consider it a bonus. Enjoy!
Q&A Library Searching Tips