A few years ago I dug up most of the horseradish roots that I had planted and put them in pots because they are fast growers and hard to control to a certain area,I haven't done anything with them since, until yesterday I pulled a couple leaves for the russian tortoises,they loved it,I was wondering if it would be safe to plant some in their enclosure where they had access to it at all times, they would probably keep them close to the ground but I don't think they could kill it, they are one tough plant, I started growing it for the manouria who like it also.