Victor abandoning arranged takeover leaves here before autumn (3,4)
I believe the answer is:
oak tree
'leaves here before autumn' is the definition.
(as in leaves on a tree)
I cannot understand how the rest of the clue works.
(Other definitions for oak tree that I've seen before include "Acorn producer" , "royal hiding place evidently" , "Product of acorn" , "Old plant (round which to tie a yellow ribbon?)" , "wood source?" .)