Paul I was under the impression Horsradish was a "Yankee" plant. IE it needs a couple months of freezing soil as part of it's dormancy cycle?? Maybe a special variety for hot weather?? L.B. Not trying to sound like an expert here but YOU MUST CONTROL SPREADING OF HORSERADISH NOW!!!! If you knew how many sites I've been on that wanted to know how to control an errant root you'd be amazed. Basically Horseradish is a weed that will take over any area and expand into other areas around it. I put 18" deep patio blocks around my horseradish bed & then tilled bed to 2'