My understanding is that they are hardy through zone 7. They are actually a deciduous hibiscus (hibiscus mutablis) if you want to do some research. They grow very easily from seed (I started some this spring and the one I kept for myself is two feet tall now in a pot.) I understand also they are very easy to root from cuttings. You might be able to collect a cutting or some seeds from a gardener near you. Right now they are in bloom here and might be for you also.