Elitist brought back excellent ornamental shrub (6)
I believe the answer is:
bonsai
'ornamental shrub' is the definition.
'bonsai' can be an answer for 'shrub' (I have seen 'Japanese shrub' mean 'bonsai' so perhaps 'shrub' could also mean 'bonsai'). I'm unsure of the 'ornamental' bit.
'elitist brought back excellent' is the wordplay.
'elitist' becomes 'snob' (I've seen this before).
'brought back' says the letters should be written backwards.
'excellent' becomes 'ai' (resembles 'A1', old-fashioned term for excellent).
'snob' reversed gives 'bons'.
'bons'+'ai'='BONSAI'
Can you help me to learn more?
(Other definitions for bonsai that I've seen before include "Tree-dwarfing art" , "Dwarfed ornamental tree or shrub" , "Japanese shrub" , "(Cultivation of) dwarf trees" , "Japanese method of cultivating miniature trees" .)