You can tell a plant is in the mint family if it has a square
stem. Mints are prolific perennials, and if you trim the tips
above the splits where new growing tips are branching
out, a patch can be harvested many times in one season.
If the leaves are pointy and have serrated edges, they are most
likely peppermint or spearmint. If the leaves and stems are
thick and fuzzy, they are apple mint. It's a little harder to see
where to trim this kind, but look closely for new baby leaves
on top of old ones (resembling tomato suckers) and cut above.
Boiling mint with lavender, bee balm (also a mint actually),
and orange and lemon rinds adds flavor. Serving with
cranberry-lemon scones doesn't hurt, either.