Woofie, that's about the same size that mine were when I transplanted them into gallon pots last year, and they grew like crazy after that. I then put them in the ground at the beginning of fall, and I didn't lose one of them over the winter. But, I don't know about leaving them in pots, since I was able to put mine in the ground. I think you'll be surprised at how well they grow when they get some leg room!
Good luck, and I hope it goes well for you!
Natalie
