Husband rejected nosegay, grasping small aromatic plant (6)
I believe the answer is:
hyssop
'aromatic plant' is the definition.
(I've seen this before)
'husband rejected nosegay grasping small' is the wordplay.
'husband' becomes 'h'.
'rejected' says the letters should be written in reverse.
'nosegay' becomes 'posy' ('posy' can be a synonym of 'nosegay').
'grasping' means one lot of letters goes inside another.
'small' becomes 's' (abbreviation - e.g. clothes size).
'posy' placed around 's' is 'possy'.
'possy' backwards is 'yssop'.
'h'+'yssop'='HYSSOP'
(Other definitions for hyssop that I've seen before include "Herb in the mint family" , "Small bushy plant with bitter minty leaves" , "Aromatic herb" , "little blue flowers" , "Aromatic plant" .)