Aw Horse...radish

Does anyone have instructions for how to make your own horseradish?

Earlier this week, my brother stopped by Jackass Acres to have a beer, and we were sitting out on the back patio. My brother is a big bear of a man, and only partially house trained. So instead of using the bathroom which is right off the back door, he deemed it more convenient to pee in back of our garage. He comes back to the table with this long leaf and tells us we have horseradish.

There is a kind of "wild" area between our garage and the neighbor's. Neither of us tend to it too much because it grows poppies, bluebells, day lillies, etc. all on its own. But in the five years we have been here, I've never seen horseradish. I wonder if her late husband planted it before he died and it's just now doing something.

So, if anyone knows when to dig it up or has a tasty recipe, please let me know. And say a prayer that my brother peed in the hostas, not the horseradish.