They are perennials, needing winter protection.
I overwintered mine and it bloomed around Christmas, then went dormant. I brought it back outside with my tropical hibiscus when the temps were steadily in the low 50's. Well, we've had a cool spring and it died; I'm assuming because it didn't like the cool temps. Sad - it was 6' tall! I have another one started and will treat it properly (hopefully) this winter. I'll probably bring it in the house.
I have heard about using it for tea, but haven't tried it myself. Here's a link -http://www.hibiscus.org/recipes.php
Barb

I grow the plant, but I haven't bothered to try and overwinter it at about $4.00 a plant--easy enough to get a new one every year. I understand it's the flowers that are used in tea, like the rosehip tea from Germany that contains rosehips and hibiscus flowers.

I've done a bit more research and apparently people do eat the young leaves in salads and stir-fries. The flowers can also be picked and blended with lime juice and sugar to make a drink.

As for the plants being easy and cheap to obtain, not in the UK they aren't! I've grown 12 from seed this year and they are such beautiful plants I will definitely try to keep some alive for next year.

I live in zone 9b, and if we have temps in the low 30's, they usually die. Normally, the 40 degree temps put them into dormancy, and they come back up. 50 degrees for dormancy is perfect.

With your short growing season, I don't suppose you get seeds, do you? I have several plants, so if you need seeds next year, let me know.

Thanks a lot for the offer. Who knows - my plants might flower, depending on where in the garden they are positioned (the back garden is north-north-west facing and gets a fair amount of shade, whereas the front is south-south-west facing, surrounded by white walls and mulched with gravel - always MUCH warmer than the back).

Good luck, but keep my name just in case. I have hundreds of seedlings coming up right now from plants I didn't get a chance to deadhead. I hate it, but I have to mow them down every week.

Ornata,
Keep Bruggirl's name. I doubt they've bloom for you outside. Mine was 9 months old before it bloomed and we have a much longer growing season than you. I suppose though, if you bring it in for the winter and keep it warm and in a sunny spot, it could.
Good Luck!
Barb