Plant providing the horticultural place with an excellent return (8)
I believe the answer is:
gardenia
'plant providing' is the definition.
'gardenia' can be an answer for 'plant' (I've seen this before). I'm unsure of the 'providing' bit.
'horticultural place with an excellent return' is the wordplay.
'horticultural place' becomes 'garden' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'with' means one lot of letters go next to another.
'an excellent' becomes 'ai' (resembles 'Ag', old-fashioned term for excellent).
'return' says the letters should be written backwards.
'ai' backwards is 'ia'.
'garden'+'ia'='GARDENIA'
'the' acts as a link.
Can you help me to learn more?
(Other definitions for gardenia that I've seen before include "Evergreen" , "Shrub such as the Cape jasmine" , "Shrub; drainage (anag.)" , "bloomer!" , "A reading (anag.)" .)