Leaves small American church clutching leg (7)
I believe the answer is:
spinach
'leaves' is the definition.
(leafy vegetable)
'small american church clutching leg' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'church' becomes 'ch' (abbreviation on maps etc).
'clutching' indicates putting letters inside.
'leg' becomes 'pin' (pin is a kind of leg).
's'+'a'+'ch'='sach'
'sach' going around 'pin' is 'SPINACH'.
(Other definitions for spinach that I've seen before include "Popeye's strength-giver" , "something to eat" , "Blackboard stand" , "Popeye's vegetable" , "Leafy vegetable" .)