I've grown hops in large planters for 4 years. I've had good luck so far, but I've learned that some rhizomes just never really do well. The first year I had 4 rhizomes, three did fine, and one grew a few feet tall and just stopped. It did better the next year, but still never for more that a few feet long. Last year I dug them up, broke up the healthiest crowns, and replanted them all. This time all four are doing well.