I have what was labelled as Polygonum bistorta 'Superbum' in my garden.
The RHS does not have it listed but does have Persicaria bistorta
'Superba'. Are they the same thing? What is the correct current
taxonmy of this plant? I assume that somewhere along the line the name
has changed but need to know which is the right name. As the 03/04
Plantfinder has it has P. bistorta 'Superna' that that is the right
name. If so then what happened to Polygonum?

Many thanks

P.