unexpected vegetable

At the beginning of summer, my brother was given a vegetable plant. He put the medium-sized pot in the garden near the house amongst the other things, and they grew up around it and he never actually put it in the ground. It got tall.

Last week I wondered about a pretty purplish flower on it, but he couldn't remember what type of plant it was.

Now we know. And there are two, growing out of a not-very-big pot. A nice surprise!