From what I've heard, so long as you keep your rhizomes in a fridge and a wrapped in a moist paper towel, they can be kept above soil for quite some time without causing any problems.
I think I read something about that on here before. Either way, you can just plant them in a large pot. That's what I'm doing. They wont be growing very rapidly for a while, and even when they do, apparently the first year is not very necessary to be using twines.