summer plants question

Just wondering how long will geraniums/petunia/lobelia will continue to survive and flower outside? 

I don't know about the others, but the geraniums can be brought inside if you want to save them for next year. Just trim the tops to about 3 inches, trim the roots to a ball, pot them up and keep on the dry/damp side. Keep them in a cool place with some light and they will return next year.

  Robbo.