Hops grow from rhizomes, and those are sold in the spring. Only the female hops plants produce the hops flowers (cones) that are used in brewing. Here's a link to a place that sells rhizomes: Freshops Rhizome Varieties
Keep in mind your climate- some hops grow better in different climates. My cascades did very well and my halletau did "ok". Cascades tend to be a high-yield plant, though, while hallertauer is a "low yield". I got about 8 ounces of dried hallertau and 16 ounces (dried) of cascades this year, the second year.
They grow about 25 tall each season, and die back each fall. I had the hallertau grow up my telephone pole in my yard, while the cascades were on a trellis.
It's impossible to know the AAUs of homegrown hops (without sending them to a lab) so I'm planning on using them for flavor and aroma. I'm thinking about other varieties of aroma/flavor hops that I like.