This houseplant, I said, traps flies (10)
I believe the answer is:
aspidistra
'this houseplant' is the definition.
(I've seen this before)
'i said traps flies' is the wordplay.
'flies' is an anagram indicator.
'i'+'said'+'traps'='isaidtraps'
'isaidtraps' is an anagram of 'ASPIDISTRA'.
(Other definitions for aspidistra that I've seen before include "Iris adapts (anag) - indoor plant" , "leafy plant" , "Houseplant of lily family" , "Star is paid (anag) - plant" , "For Asian native" .)