House plant's site? In a pot, strangely! (10)
I believe the answer is:
poinsettia
'house plant's' is the definition.
(I've seen this before)
'site? in a pot strangely' is the wordplay.
'strangely' is an anagram indicator.
'site'+'in'+'a'+'pot'='siteinapot'
'siteinapot' with letters rearranged gives 'POINSETTIA'.
(Other definitions for poinsettia that I've seen before include "American plant" , "Shrub often given at Christmas" , "Plant with showy bracts, usu. red, pink or white" , "Ornamental house plant" , "Flower popular at Christmas" .)