Scoundrel climbed for wild plant (3,4)
I believe the answer is:
dog rose
'wild plant' is the definition.
'scoundrel climbed' is the wordplay.
'scoundrel' becomes 'dog' (dog is a kind of scoundrel).
'climbed' becomes 'rose'.
'dog'+'rose'='DOG-ROSE'
'for' is the link.
(Other definitions for dog rose that I've seen before include "wild shrub" , "Hedgerow plant" , "something smelling nice in the hedgerow" , "Flower of the hedgerow" , "bloomer" .)