How long do you plan to keep it in a one gallon and is the root ball small right now? I only hold mine in one gallon for a while until I decide where to plant and if it ends up staying in there a while, I pot it up into bigger pots so as not to risk stunting it in any way and I also don't want to risk it overheating or getting dried out. I do grow a couple permanently in containers but they are the largest sized as I can get them.
Bee's Jubilee can be a big plant so eventually it should get planted to reach it's full potential.