Leafy vegetable ending in trash breaking heart, say? (5)
I believe the answer is:
chard
'leafy vegetable' is the definition.
(chard is a kind of leafy vegetable)
'ending in trash breaking heart say?' is the wordplay.
'ending in' indicates one should take the final letters.
'breaking' is an insertion indicator.
'heart say?' becomes 'card' (hearts is a playing card suit).
The final letter of 'trash' is 'h'.
'h' inserted inside 'card' is 'CHARD'.
(Other definitions for chard that I've seen before include "Seakale beet" , "salad" , "Leaf stalks from a kind of beet" , "Variety of beet with edible leaves" , "Green vegetable" .)