Gas lines are 'supposed' to be 18 inches deep here too, but I can tell you, especially for older homes that some lines are not nearly that deep. It can be dangerous to hit one. That being said, they are tough, so gentle hand digging will suffice, just pay attention. If you run into the line, just dig around it. My hosta don't root very deep anyway and if you do cut quite a few roots, it will not hurt the hosta, the important thing is to not damage the crowns. You can even wrap them in wet newspaper for a few days-just lay them in the garage or utility room until you re-plant them. They will not look like anything again this year probably, but I bet next year, you will not even know they were messed with.
