It looks a bit more like peppermint than spear to me but just taste it and you will know for certain. Mints are herbaceous perennials and they go dormant in Winter. They are not evergreen and it is normal for the top growth to die back to the ground. Personally I would cut it back and harvest as much as possible before your cold weather starts. You could try digging up a root and keeping it indoors in a pot to extend the season a bit but it won't be ideal.

Thank you! I'm using as much as I can in pies, cakes, and mint chocolate cookies. Also I freeze them in ice cubes for juice.

I am in central Ohio, Looks to me like it is simply responding to the winding down of the season. Mint dries extremely easily, no need to be a glutton and use all the fresh stuff you have! ;-)

As far as whether it is spearmint or peppermint, I always suggest a person taste a leaf, eyes closed. If you think of toothpaste, it is likely spearmint. If you think Christmas and candy canes, it's probably peppermint. But if you like the taste, who cares which it is? (In general I think spearmint generally has pointier leaves than peppermint - but the mints all hybridize so readily, who knows!)

T propagate more, just cut off (usually about 6") stems, strip off all but the top couple of sets of leaves & put them into a container of water - not letting the water touch the remaining leaves - and put it in a sunny window (or under lights if you have them). Indoors in winter the air is dry; a container can lose water rather quickly, so monitor the water to maintain a high enough level to cover the stems, especially once the roots begin to show.

You could root as many cuttings as you would like plants next spring, and if you cut large, branched sprigs (assuming you have the room on a windowsill) you could conceivably enjoy at lest a little fresh mint through the winter. Enjoy!

Thanks! That was actually quite helpful.