Ditching goods and trading positions, Greta Garbo gardens (8)
I believe the answer is:
arboreta
'gardens' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for arboreta that I've seen before include "shady gardens?" , "Rare boat (anag) - botanical tree gardens" , "wooden displays" , "tree plantations" , "growth areas" .)