Flower bed primarily in Genoa running wild around unit (7)
I believe the answer is:
begonia
'flower' is the definition.
(begonia is a kind of flower)
'bed primarily in genoa running wild around unit' is the wordplay.
'primarily' suggests taking the first letters.
'in' is an insertion indicator.
'running wild' is an anagram indicator.
'around' indicates putting letters inside.
'unit' becomes 'i' ('I' can be a synonym of 'unit'**).
The initial letter of 'bed' is 'b'.
'genoa' is an anagram of 'egona'.
'b' placed within 'egona' is 'begona'.
'begona' placed around 'i' is 'BEGONIA'.
(Other definitions for begonia that I've seen before include "Common garden plant" , "Tropical plant" , "colourful flower" , "bloomer" , "Herbaceous plant whose flowers have no petals" .)