Plant is right outside church (6)
I believe the answer is:
lichen
'plant' is the definition.
(lichen is a kind of plant)
'right outside church' is the wordplay.
'right' becomes 'lien' (I've seen this before).
'outside' is an insertion indicator.
'church' becomes 'ch' (common abbreviation).
'lien' enclosing 'ch' is 'LICHEN'.
'is' is the link.
(Other definitions for lichen that I've seen before include "Tiny plants growing on rocks and treetrunks" , "Small plants found on tree-trunks and stones" , "Symbiotic organism growing on a tree trunk or rock" , "Growth found on tree trunks and rocks" , "Tiny green, grey or yellow plant found on rocks or trees" .)