Charlie helps after banks rejected father saving up for fruit tree (4,5)
I believe the answer is:
crab apple
'fruit tree' is the definition.
(crab apple is a kind of fruit tree)
'charlie helps after banks rejected father saving up' is the wordplay.
'charlie' becomes 'C' (phonetic alphabet: alpha, bravo, charlie etc.).
'after banks rejected' means to look at the middle letters (edges or banks of the word are removed).
'father' becomes 'pa' (pa can mean dad or father).
'saving' becomes 'bar' (I've seen this before).
'up' says the letters should be written in reverse (in down clue: letters go upwards).
The middle letters of 'helps' are 'elp'.
'elp'+'pa'+'bar'='elppabar'
'elppabar' backwards is 'rabapple'.
'c'+'rabapple'='CRAB-APPLE'
'for' is the link.
(Other definitions for crab apple that I've seen before include "Tree bearing fruit for jelly" , "Wild fruit used for jam" , "Sour fruit used for jam or jelly" , "A small sour fruit - will it keep the doctor away?" , "unappetizing fruit" .)