Greetings from the Rochester-Finger Lakes area!

Mint is deciduous. Put it back outdoors and it will turn brown and loose all its leaves - normal behavior with the coming winter. Evergreen means it would be like a pine or a rhododendron, which doesn't have leaves that brown and drop in the fall. It stays green all year long.

Hardy perennials take the odd cold temperatures in stride and can bounce back from them. It may be hard to over winter your mint indoors. Do you have a place where you can sink the pot into the soil outdoors? Mother Nature usually does a much better job overwintering hardy plants than us humans! I would, however, take a few cuttings so you can have some winter fun by starting some other new mint plants.

FataMorgana

Mint is a tender herbaceous perennial, meaning that it will die down to the ground in a hard freeze, but regrow from the roots in the spring. If such a plant is kept inside for the winter, it will simply not die back. We don't qualify herbaceous plants as 'evergreen or deciduous'. They are herbaceous.

I'm not sure what I was thinking since I know better. Rhizo is correct. "Herbaceous" is the proper term. Though I must say that I only use the term "tender" with plants that will not survive winter weather at all. Even local nurseries and garden centers use it to mean the opposite of "hardy."

As long as you have a more common mint variety like spearmint, peppermint, etc., it will easily survive zone 5 winters and resprout in the spring so long as it is planted or its pot is sunk into the ground.

FataMorgana

Yes.....between the two of us, we'll get the terminology right, lol. I agree with your use of the words hardy and tender.