Boy, you posted this one everywhere, didn't you, Eric? I keep bumping into it on different forums, so I guess I'll have to answer it! ;-)

I usually cut back the individual stalks when they start to look ugly, whether that be yellowing, browned leaf margins, whatever. It's mostly an aesthetic thing, because they'll send out new shoots anyway, and those will flower when they're ready, although removing the old ones may encourage new ones a bit quicker. Just don't cut them all back at once, it may have the oposite effect and weaken the plant. If you want to get seed, though, you should wait until the seed pods pop open before you cut that stem back.

I live in a year-round growing climate, though, so I don't know if these have any kind of a dormancy where you are.

Hi, Yes, I did post this in a few applicable forums. I thought I might increase my chances of getting an answer. Thank you for yours!
Eric

I find this to be one of the least rewarding plants I have in my collection. Mine almost ALWAYS looks ratty. I love the blooms, though.