Never grown potato mint, but many mints can be very vigorous, given the right conditions. People complain about it often.

You might need to move it to an even larger pot...

It grows like mad, and makes a great ground cover. Roots easily, like all mints. You can cut it back if it gets out of hand, and it will still make potatoes.

That being said, it can be a bit aggressive, but not invasive. It roots to the ground wherever it touches, and can leave teeny tiny potatoes in the ground that come up the next year. I thought all of mine was dead, then it started coming up in every pot it had been in and in one spot in the garden where I was sure it had died.

I'm going to use mine as a ground cover to keep some weeds down. It dies back in the winter and comes back in the spring, stronger than ever.

I use it as a great summer ground cover but it goes completely dormant it the winter and that's when I harvest it. Its very manageable.

Glenn, thank you. That's the word I was looking for -- manageable. I'm about to cut some of mine back to give cuttings to a friend.

Thank you all. It do root very easily... I stuck two cuttings in soil and they are taking off. I will try it in an area mainly to suppress weeds over the summer and try the potatoes this winter!