"Sang a Verdi Requiem last night, under Vladimir Jurowski (chance'd be a fine thing...)"

I see your point... hmmm.

As to the pieris, don't have an answer, but perhaps someone on this forum might: http://mygarden.rhs.org.uk/

If you can't find anything helpful let me know and I'll see how I invoke my free advice for being a member of t'RHS.