Hi

Yes terra cotta pots will freeze and crack. They are pourous and soak up water. The plants roots would freeze too.

Lemon Balm is no problem if you put it in the ground. Just make sure you cut off the flower heads so it doesn't go to seed or you'll have it coming up all over. In fact don't let any of them go to seed unless you want to be pulling out plants in the spring. A haircut with clippers is called for.

With your other mints you can put them in the ground if you contain them. If you can get a hold of a couple of those black plastic pots that shrubs come in, they are ideal or any pail or pot that is about 10 inches deep and you can cut the bottom out of. Cut out the bottom and sink the pots into the ground leaving the rims about 3/4 inch above the ground. Now plant your mint inside the pot/pail.

You will have to thin them out every spring so they don't get rootbound, but they won't become invasive

I agree with Oilpainter - plant the mint in pots which are sunk into the ground with the rim sticking out (so the plants don't spread over the edges)

Here is a link that might be useful: growing mint

I plant my mints in very large (about 30 gallon) tufa pots which stay outside all winter and don't crack or break. They are fairly expensive but well worth it in my opinion.

I have most of mine in pots away from the soil.
I have spearmint growing wild in a small partition. It grew there from a potted spearmint that was in a tiny pot on the ground. A root must have escaped through the bottom. Needless to say I have about a 3-4' spearmint plant now that is growing wild. It's okay as I like it where it's grown. Just letting you know that no matter where you put it - its likely to escape!

Barbe
You can make your own tufa pots. All you need is peat and ready mix cement and a pail or pot for a mold. I'm sure you can find directions on line. I have a friend who makes them and she's used them for planters and even made a fountain out of them

Don't know if it's NZ lemon balm or climate that's different, but it's a major thug in gardens here.
Like its pushy cousins, it spreads through stolons as well as seeds. Makes great tea though!

I live in the south, and a lot of things in the mint family are invasive.
However, my experience with putting applemint in a pot in garden soil....it grew right out of that pot in no time. Didn't put the rim above soil line, but not sure that would've helped.
Like the beebalm it keeps spreading and spreading....
I put my peppermint outside of garden, but it doesn't seem to like it's location ( not enough sun I think) and it's not doing as well-but still spreading. Need to move it this fall. However, it will be outside of raised, established beds, in a place it can go wild.

Can I plant terra cotta pots in the ground with mint in them? Do I have to remove the bottoms?

Also, do the runners put roots down? People are talking about planting the pot 3/4 in above ground to prevent the plant from spreading. But the runners will still stretch out beyond the pot. Will they put roots down and create new plants?

I plant mine in large tufa pots that can stay outside year-round. If you sink the pots in the ground, you will need to cut off the runners, and in any case don't let it go to seed.

The roots will go right out the bottom of any pot... and make new plants. And, yes, the runners will set roots.

i transplanted 3 types of mint to a spot in the middle of my lawn in a row with the berry bushes. they are separated 8ft. on either side from the berries by lawn. when they try and spread into the lawn they get mowed down. so far they haven't moved beyond their plot. it smells great in the yard when i mow and keeps the bugs away from my berries that are nearby!