Not for those who would mighty oaks from acorns grow? (6)
I believe the answer is:
bonsai
'for those who would mighty oaks from acorns grow?' is the definition.
The definition suggests a singular noun which matches the answer.
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for bonsai that I've seen before include "small growth" , "Art of dwarfing trees" , "Tree-dwarfing art" , "Japanese plant or tree grown in miniature form" , "Potted tree or shrub artificially prevented from reaching normal size" .)