Need to stop by Sudanese recycling plant (5-4,5)

'plant' is the definition.
(black-eyed Susan is a kind of plant)

'need to stop by sudanese recycling' is the wordplay.
'need' becomes 'lack' (to lack something is to be in need of it).
'to stop' means one lot of letters goes inside another (stopping can mean blocking a gap).
'recycling' is an anagram indicator.
'by'+'sudanese'='bysudanese'
'bysudanese' anagrammed gives 'beyedsusan'.
'lack' inserted within 'beyedsusan' is 'BLACK-EYED SUSAN'.