I recommend if you want to grow hops, do not buy them from a seed catalog, rather order them from a hop farm or through a homebrew shop who bulk orders them from a farm. Most all homebrew shops, particularly the large online sellers offer hop rhizomes. Hurry though as they will either be close to sold out or already all spoken for. I ordered some from a hop farm in Colorado this year and am going to give it a try although I don't have the ideal climate to grow. I ordered some Cascade's and Chinooks.
In regards to the climate, where do you live? Most of the successful hop growing occurs in the northern area. Oregon, Washington, and Idaho are the prime growing regions. You can grow them anywhere, some areas are just easier to grow in. As I mentioned I am going to try some. I will have to work a lot harder than those in the northers regions. Also as I said, try to buy from someone who has a good quality stock.
There is tons of info on the Inter web about hop growing. One of the beer forums I lurk at has a pretty active hop growing sub forum. I have learned a lot from there. I really need to get my butt in gear and get my spot ready this week. They will be shipping soon.