Plant joint tenants outside of town (4,4)
I believe the answer is:
tree fern
'plant' is the definition.
(tree fern is a kind of plant)
'joint tenants outside of town' is the wordplay.
I cannot really understand how this works, but
'joint' could be 'reefer' (informal term for a marijuana joint) and 'reefer' is found within the answer.
'town' could be 't' (abbreviation for town) and 't' is found in the answer.
A single letter 'n' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for tree fern that I've seen before include "Tall plant" , "tropical plant" , "Palm-like plant" .)