As I'm pretty sure you've noticed, I'm a big fan of horseradish. And I really prefer the fresh stuff to the jarred. The stuff in the jar is fine...but it's pretty vinegary, and the fresh stuff can really knock your socks off (and I love having my socks knocked off!) I'm in the middle of an experiment this summer. I bought a horseradish root at the store, broke off the top end, planted it, and look at what I have growing!
I'll let you know how it goes, but word is the more you ignore it, the happier it is. And, like mint, horseradish will apparently take over your yard... so containers are the way to go!