Plain ugly green ties (9)
I believe the answer is:
serengeti
'plain' is the definition.
(I know that Serengeti is a plain)
'ugly green ties' is the wordplay.
'ugly' is an anagram indicator (an ugly or wrong form of the letters).
'green'+'ties'='greenties'
'greenties' is an anagram of 'SERENGETI'.
(Other definitions for serengeti that I've seen before include "region in Tanzania" , "place to watch game" , "Vast plain" , "Afr. plain; green site (anag.)" , "where lion holds sway?" .)