[Nepeta]

This looks really interesting, especially for those living in warm parts of the country, or with greenhouses:

http://deepgreenpermaculture.com/diy-instructions/grafting-eggplant-onto-devil-plant/

This applies not only to eggplant, but to tomatoes. Imagine growing tomatoes as perennials!

[Ellendra]

I have a tomato that’s been growing in my bedroom for 4 years now.

I wouldn’t recommend them as a houseplant, really. With mine, the vines keep growing longer until they collapse on themselves, then they branch and start growing longer again. I currently have a 5 foot tall mess of vines, with leaves growing on the last 3 feet only, making the rest look dead even though it isn’t. And it doesn’t get enough light to produce fruit more than once in a blue moon.

However, it’s very handy for taking cuttings in the spring.