posted 12 years ago
As far as the difference between Bocking 4 and 14, I think it depends on who you ask (and what they sell).
The B-4 is supposed to produce more biomass, (and have a higher protein level than the B-14).
I've grown both, but never side by side, so I cannot either deny/confirm this.
I have heard claims that B-4 is hardier than B-14, but from what I've heard, all 3 are hardy to USDA Zone 3.
Personally, I don't see that much difference between the three unless...
...you are getting it strictly for medicinal purposes (in which case, get the true comfrey), or
...you don't want it to spread by seeds (in which case, get one of the Bockings).
As far as the question regarding International shipments, you may be limited to true comfrey. True comfrey sets viable seeds. International regulations are usually a little less restrictive for seeds than for live plants. And I would rather receive a packet of seeds that spent a month in the postal system than a live (?) plant.
The US, and Canada each have numerous vendors, and the UK has several (that's where the Bockings originated), so shipment within the EU shouldn't be too big of a problem.
Good luck.