Plant spades on the verge (5)
I believe the answer is:
sedge
'plant' is the definition.
(sedge is a plant)
'spades on the verge' is the wordplay.
'spades' becomes 's' (abbreviation in card games).
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'the verge' becomes 'edge' (I've seen this before).
's'+'edge'='SEDGE'
(Other definitions for sedge that I've seen before include "plant with triangular stems" , "Grass-like plant growing in wet places" , "fly by rivers" , "Coarse grassy plant" , "Grass-like plant growing in marshes" .)