Plant that's the result of poor drainage (8)
I believe the answer is:
gardenia
'plant' is the definition.
The answer is an example.
'poor drainage' is the wordplay.
'poor' indicates an anagram.
'drainage' with letters rearranged gives 'GARDENIA'.
'that's the result of' acts as a link.
(Other definitions for gardenia that I've seen before include "Fragrant tree or shrub" , "Waxlike flower" , "A reading (anag.)" , "bloomer!" , "Bad drainage can produce a fragrant flower" .)