I have a large terrace in New York City, and am looking to fill it with some greenery without spending a fortune. In the past I have had good luck with morning glories in containers - they grow quickly, are very cheap of course, and have nice flowers.

However I'd like a little variety and also flowers that didn't only bloom in the morning would be nice. I've tried moon flowers but could never get them to bloom.

I also tried passion flowers but they did not grow that quickly, and the vines did not branch out much so there was not much volume to them.

So can anyone recommend some others? I guess I'd prefer to plant seeds, but I'm not too picky about that.