I have a standing offer for everyone each spring. Come dig horseradish!! I started a small patch several years ago in a raised bed. We wound up with roots the size of ball bats and it started spreading. No problem. I moved it to the main garden so I could control it with the tiller. Turns out horseradish is propagated by chopping up the roots and burying it. Kind'a what a tiller does. Roundup™only tickles it, Diquat™  just brown the leaves. I think it's really Indiana Kudzu. Wahoo took some 3 yrs ago for his garden :)