I have a hazy memory of sowing a few seeds of this several years ago - but I haven't done since, yet it pops up in some corner of my garden every year.
These lovely sky-blue flowers remind me of auriculas in the way they have those perfect white circles in the centre. They couldn't be more different in habit though - Nicandra is a big, beefy, fast-growing plant to about 4ft high with lush, almost tropical foliage. It's supposed to repel flies - hence the common name - and some use it as a companion plant to get rid of cabbage whitefly and the like.
The charms of these pretty blooms are fleeting - they last just a few days, and even then they won't open if it's not sunny. But the spectacular seedpods are worth all that coquettish reticence: they're delicate papery lanterns some two inches across that start vivid green and turn nut-brown with age. They last for ages (if the kids don't pop them all first) and shed their seeds generously: weed out all but one in only the places you really want them, or there won't be room for anything else.