Sell a herb, possibly, or some plants (9)
I believe the answer is:
harebells
'some plants' is the definition.
(harebell is a kind of plant)
'sell a herb possibly' is the wordplay.
'possibly' indicates anagramming the letters.
'sell'+'a'+'herb'='sellaherb'
'sellaherb' anagrammed gives 'HAREBELLS'.
'or' is the link.
(Other definitions for harebells that I've seen before include "Flowers" , "Wild type of bloomers" .)