You can stake them just to help prop it up or in Spring separate them into their own smaller containers and stake again till it anchors itself much better. Just to add, I do quarter turns of the container since it will naturally seek bright light, to help it grow a bit more upright.
I was able to separate mine before when I got it, did not have to cut anything. It was good to see easy enough to separate the rhizomes carefully, I have a barbecue skewer to gently untangle the roots and a brush to carefully stuck soil. But I did this in April, mid-Spring time so conditions are warmer already.
