Mint

*Mentha*

How to know it

Square stems, paired toothed leaves, and an unmistakable smell. Spreads by underground runners, aggressively.

What it does

Used in drinks, cooking and traditionally for digestion. The cooling sensation comes from menthol acting on cold receptors in the mouth, which is a genuinely strange fact worth telling older children.

Safety

Safe. Grow it in a container unless you want it everywhere, which is a lesson in itself.

Two things to do with children

Plant mint in the ground in one corner and in a pot in another. Come back in three months. The comparison teaches invasiveness better than any explanation.

Let children feel the square stem. Square stems mean the mint family, and it is one of the few identification shortcuts a young child can actually use.