Art of growing dwarf plants (6)
I believe the answer is:
bonsai
'art of growing dwarf plants' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for bonsai that I've seen before include "Japanese art of growing dwarfed trees" , "Japanese craft of growing dwarf trees" , "Little Japanese growth" , "The art of growing ornamental dwarfed plants" , "Japanese plant or tree grown in miniature form" .)