Bush in backlash? Rubbish (5)
I believe the answer is:
shrub
'bush' is the definition.
('shrub' can be a synonym of 'bush')
'in backlash? rubbish' is the wordplay.
'in' indicates the answer is hidden within the clue.
'SHRUB' is hidden within 'backlash rubbish'.
(Other definitions for shrub that I've seen before include "Small woody plant" , "Cordial" , "Drink of rum, fruit juice and spices" , "Perhaps Heather" , "Brush? (anagr.)" .)