I once grew a large plant over a 10 year period. When planted it was large
already, so I dug a hole in my flower bed that was 24" wide by 1 foot in
depth. I inserted a vinyl plastic and placed sphagnum moss within it. The
plant was kept constantly wet (bog-like) and rain water or tap water was
used. When tap water was used, I allowed it to sit overnight if I could help
it. It grew in a sunny location and because of this it was red and green in
color. It received below freezing termperatures over the winter and snow
cover.
Good luck
Rob