I've just lived here for about a year so I'm not sure...I assume it's annual though.
BTW, you have a lowland setup? I have an N.ampullaria I'm killing because of cold (I assume) and I'm sure shipping it off would kill it, but handing it off to someone who has the setup will probably save it.
thez- yo: Well my set up is very easy maybe you can try it too.
I have my N. Amp. in a cabinet with 2 lights. 1 compact fl. 27watts (I think) and the other a 18inch 15 plant and aquarium... 2gal of water right bnext to it for "humidity" and that's all!! And ill tell you... its putting some really nice pitchers... oh yeah the light source is about a foot... tha't all nothing fancy and very easy to set up!
Jag: I don't want to set up anything than shelves in front of a window, so it's really my fault it isn't growing so that's why it needs a new home. Thanks for the suggestion though because it sounds great, but with the amount I spend on plants, I don't want to also be spending money on aquaria, bulbs, electricity, etc.