Shelter, having a smoke in greenery (7)
I believe the answer is:
leafage
'greenery' is the definition.
(I've seen this before)
'shelter having a smoke' is the wordplay.
'shelter' becomes 'lee' (as in lee side, the side sheltered from wind).
'having' indicates putting letters inside.
'smoke' becomes 'fag' (both can mean a cigarette).
'a'+'fag'='afag'
'lee' placed around 'afag' is 'LEAFAGE'.
'in' acts as a link.
(Other definitions for leafage that I've seen before include "Greenery" , "Green growth" , "Gala fee (anag)" , "marijuana, possibly" , "Foliage" .)