Foliage supplied by conservationist with hesitation meeting youth leader (8)
I believe the answer is:
greenery
'foliage' is the definition.
(greenery is a kind of foliage)
'conservationist with hesitation meeting youth leader' is the wordplay.
'conservationist' becomes 'green' (I've seen this before).
'with' says to put letters next to each other.
'hesitation' becomes 'er' (sound made while hesitating - um, er).
'meeting' is a charade indicator (letters next to each other).
'youth leader' becomes 'y' (I've seen this in other clues).
'green'+'er'+'y'='GREENERY'
'supplied by' is the link.
(Other definitions for greenery that I've seen before include "Living foliage or vegetation" , "Foliage etc" , "something naturally colourful?" , "colourful stuff?" , "Decorative boughs" .)