how can I conserve horseradish from my garden?

Here's how you can it: http://nchfp.uga.edu/how/can_06/pickled_horseradish.html

http://www.newsobserver.com/2012/11/16/2485819/tasteful-garden.html

I've frozen whole, washed unpeeled roots successfully. Just peel and grate in their frozen state. You can also freeze prepared horseradish. It stays potent longer than it would kept in the fridge, but still it gradually loses punch.

I've read that you can pack whole roots in canning jars and cover them with vinegar, but I've never tried that.