I just read a care sheet from Just Fruits http://www.justfruitsandexotics.com/JF%20ContainerCitrus.pdf stating that you should trim 1/3 of the roots if they should out grow the container they are in. I've always questioned what would happen once the roots start outgrowing the container, but is this the recommended process? I have a tangelo on FD rootstock that was planted a few years ago in a half wine barrel. I also have a Gold Nugget mandarin on an unknown rootstock (labeled semi-dwarf from Durling's Nursery) that was planted last year in a half wine barrel.

Should I be pruning roots periodically? How much and how often (if at all)? Best time of year?

Any ideas what rootstock my "semi-dwarf" might be?

Thanks,
Phillip