Cheer and queen produces a flowering shrub (8)
I believe the answer is:
oleander
'a flowering shrub' is the definition.
(I've seen this in another clue)
'cheer and queen' is the wordplay.
'cheer' becomes 'ole' (I've seen this in another clue).
'queen' becomes 'ER' (abbreviation for Elizabeth Regina).
'ole'+'and'+'er'='OLEANDER'
'produces' acts as a link.
(Other definitions for oleander that I've seen before include "bloomer" , "Adore Len (anag.)" , "Poisonous evergreen shrub with white, pink or red flowers" , "No dealer in evergreen shrub" , "tree" .)