Flower in Europe that chokes slender shrub (8)
I believe the answer is:
oleander
'shrub' is the definition.
(I've seen this before)
'flower in europe that chokes slender' is the wordplay.
'flower in europe' becomes 'oder' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'that chokes' indicates putting letters inside.
'slender' becomes 'lean' (similar in meaning).
'oder' enclosing 'lean' is 'OLEANDER'.
Can you help me to learn more?
(Other definitions for oleander that I've seen before include "'Adorn eel, badly, with this shrub (8)'" , "Flowering plant" , "No leader, oddly, for the flowering shrub" , "Mediterranean shrub" , "Poisonous evergreen shrub with white, pink or red flowers" .)