Ugly type of growth needing no publicity (6)
I believe the answer is:
ogress
'ugly type' is the definition.
(I know this)
'growth needing no publicity' is the wordplay.
'growth' becomes 'progress' (growth can mean progress or development).
'needing no' is a deletion indicator.
'publicity' becomes 'PR' (public relations).
'progress' with 'pr' removed is 'OGRESS'.
'of' acts as a link.
(Other definitions for ogress that I've seen before include "Female giant in fairytales" , "Female giant in fairy tale" , "earsome lady" , "Female monster" , "Man-eating giantess" .)