A social climber raised one plant (6)
I believe the answer is:
bonsai
'plant' is the definition.
The answer is an example.
'a social climber raised one' is the wordplay.
'social climber' becomes 'snob' (I've seen this before).
'raised' says the letters should be written backwards (going up in a down clue).
'one' becomes 'i' (Roman numeral).
'a'+'snob'='asnob'
'asnob' back-to-front is 'bonsa'.
'bonsa'+'i'='BONSAI'
(Other definitions for bonsai that I've seen before include "Mini-tree growing" , "specimen with restricted roots?" , "Dwarf tree found in Bosnia" , "Japanese art of growing dwarf trees" , "Japanese craft of growing miniature trees" .)