1) purchase seed & start that way (not true from seed collected from your plant) (2) cuttings have not worked (3) division in wall or very early spring.

Root cuttings in winter. I'm about to do some here in Australia. (I believe it might have PBR)

they root easily in water, this is true, but for me i've found that plants root easier if you put them in soil in a baggie, close the baggie 3/4 the way, oh ya, don't forget the rooting hormone, and then put them in the soil, mist them, then blow into the bag, then while the bag is full of air still, close the bag, so when the bag is closed it will be totally full!! hang it up with a clothes pin or something, my stuff rooted in a few weeks, and it was great!! not having to keep misting it all the time. i even rooted ivy that i havent been able to root, ever!! now i'm working on some passiflora and peony, the peony busted so i thought why not?? :'))