And the winner is:

The convolvulus. (Yes, it's windy today.)

Notice two things. One, they're remarkably pretty. I hadn't expected that. And two, they're blue! There's a flower after my own heart! What I seeded is a mix, so it could have been anything... but the one that came up is blue. How sweet!

Technically, I know that the convolvulus did not deliberately make blue flowers because I was annoyed and blue is my favourite colour. It's purely random. Nonetheless, it's making me happy.

This is not the only convolvulus vine, so I might get some other colours yet, but I'm thinking I'll cull the non-blue ones and harvest the seeds from the blue ones. Like a Neolithic man.