I have been following this discussion with interest because, like all of those who have contributed, I find labelling either absent or basic in Rome.
Umbrian's message perhaps contains the seed of one thing we could do as an organisation. I have seen that some of us are opposed to legislation. But the labelling we find on our foodstuffs and clothing etc has all come about through legislation and is a thing which we expect as a matter of course. Thinking along the lines of legislation the organisation could, as has already been suggested above, draw up a list of basic information needed on a plant label and then send out a blanket press release to all euro MPs and potentially interested gardening societies and magazines. This would probably have costs. I have heard that there is a fee to pay if you want to blanket email all UK MPs, for example.
Of course, we need also to be considering the organisation's potential advisory role if euro MPs take the case up. And to this end perhaps we should be looking to ask members to contribute to a data base logging their successes and failures. It would be worse than useless to get the legislation and then find that the information found on the label in Rome, Madrid, Tel Aviv etc was invalid because it was a straight copy of information relevant to northern Europe. For example, hardiness data is very useful but what about heat tolerance? Looking at the literature there is very little information available and this factor would probably count for 90% of my failures.
It would be unfair to criticise producers for not including this information when it is not readily available. We might consider furnishing this information from our hands-on experience. How could producers know, for example, that attempting to grow crocosmia in Rome is almost certainly doomed to failure? I have to keep the one or two that I get to survive in a light space but with no direct sun. Otherwise in summer they burn to a frazzle. Not the information a producer would be giving a purchaser in my home town of Leeds in the UK.
Hope I haven't repeated anything already stated in mailings above. I confess I haven't read all the emails in this chain.