Quality improved for nursery product (8,4)
I believe the answer is:
standard rose
'quality improved for nursery product' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'quality improved for nursery product' is the wordplay.
I cannot quite understand how this works, but
'quality' could be 'standard' (standard is a kind of quality) and 'standard' is present in the answer.
'product' could be 'os' (OS is an example) and 'os' is present in the answer.
The remaining letters 're' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for standard rose that I've seen before include "Chelsea exhibit? - with 19a" , "Competitors better this year maybe" .)